It seems to me there is a huge number of hunters who simply can not wrap their head around where buckshot comes into play. That is no fault of the hunter, they simply have not experienced an environment that favors close and quick shots. The best way I can explain it, is to give stories and examples.
I hunt deer in central MN, which is mixed woods, fields, and swamp. Emphasis on the swamp. You could set up on a field, but you won't shoot a full grown buck that way, at least not without having access to a bunch of fields, and scouting day after day. You can certainly shoot a doe or small buck that way. A ton of hunters set up in the woods, which sometimes works, but it is more complex than you would think. Woods is not woods. Especially on public land, you can guarantee everyone and their brother has sat, and probably smoked in the big woods of any public land. The big problem I've found, both public, and private land, is that deer have figured this out. MN can range from gently rolling land to extremely hilly. Deer love to bed and travel on the high ridges. They know they can see and smell everything there. There is almost no way you can get in and set up without them seeing or smelling you. The swamps are a hidden gold mine that no one will exploit due to the physical difficulty it can be to hunt them. Deer know these areas are safe, and they love side cover which open woods do not afford. Big bucks don't wander into most agricultural fields in the day, and any that wander through the woods are killed on day one by bow hunters. The very best tactic I've developed for big bucks in MN is to hunt travel corridors, and that almost always involves the swamps. MN swamps are wet, full of 6 foot plus tall cattails, thorns, and dead/fallen trees. Deer don't just slowly meander through these areas, usually they are walking erratically (they don't like to be wet either), or trotting, but swamps do funnel them well.
The first example has happened to me time, after time, after time. We were not allowed buckshot in Minnesota, and I can count on a huge missed opportunity every year because of it. I set up in an area that I know is a heavily used deer trail, but the brush only allows a few narrow shooting windows. Inevitably, a deer comes trotting through, I pull up, and I can't get him to stop in the clearing, which is rarely more than a window wider than a deer length. Off trots the buck. Now lets take that same scenario, and use a shotgun with buckshot. You have a gun that is made to be used on moving targets, and you have ammo that is made for moving targets. I see a buck I like coming, pull up the shotgun, and bang, roll him in his tracks at 20 yards.
So some say why not just shoot a bullet? Look, I'm not an expert shooter. I'm better than the average shooter. I shoot shotgun on clays most of the year, thousands of rounds down range. I duck hunt all fall, and have plenty of practice by deer season. Do I feel confident taking a trotting deer at 20 yards with a slug, ball, or bullet? Probably, depending on the gun. If I were smart enough to go out with a well fitted shotgun with a ball or slug, then I probably would. Since I usually go for the rifle, it isn't as easy. And lets say it turns out to actually be 40 yards. Then no, I would not feel comfortable taking that shot with a single ball, but would definitely take it with buckshot as long as they were moving slow enough. Low brush adds a lot of shooting difficulty that big woods, or open field shooters can't understand.
The second example would be one I'm currently trying to work around. There is private land I've been hunting since I was a little kid. This particular spot is where I shot my first ever deer. It used to be that deer ran north and south on a main trail, and shots were close, but relatively open. About 10 years ago, someone built a house not too far away on that deer trail, cut down all the trees and everything. So now the deer move more N to SW, and do not go through the open any more. I've moved a stand to allow perfect 15 to 30 yard shots, but have not hunted it in years. The problem is there is now a house about 400 yards downrange. It is shooting into a hole, with a large hill for a backstop, but I still don't feel comfortable shooting a ball or slug that direction.
So some say why not move the stand? Well I could, and am contemplating it. This is near the property line, so options are limited. In the other spot, it would require a ton of clearing trees to cut shooting lanes, which would work, but unless I cut down half the woods, we are back in scenario #1, although in this instance deer usually only walk through, rather than trot. The other option is to bow hunt. I shoot bow from time to time, but I'll admit I find it real boring after a while. Crossbows are legal in the firearms season, but it doesn't seem right to buy something just to cheat. The ideal solution for me would be buckshot. Shooting in this spot downhill, with that large of a hill for a backstop, I would not be afraid of buckshot being a danger.
The last scenario seems to be controversial, and that is running deer. I had the unfortunate instance last year of having to make a split second decision to either make or break the season. I had hunted all season after one of a few bucks on private land, and I was down to about 4 days left in the muzzleloader season, our last season. I was sitting against a tree in a relatively open travel route for deer with my TC renegade rifle. A buck I was after came from straight behind me at a gallop on the trail only 20 yards or so from me. I raised the rifle and made a noise to stop him. Instead of stopping, he turned and went full speed. I was given a perfectly broadside 40 yard shot, and I took it. He ran full sprint for 50 yards, stumbled, made it 50-75 more yards and fell over dead. I had made a perfect double lung shot. There is a more sad outcome to that story, but that was no fault of the rifle, and that is for another day.
So some say, where's the problem? I made a perfect shot. Let me tell you, "nail biter" does not even begin to describe the pressure of trying to put a single ball in the exact spot you need to on a buck you've hunted all season, 4 solid days of the last week of the season in December, on a deer running full speed. If it had not been for a season of practice on moving targets, and an extremely cool head when I needed it, a lesser hunter may not be able to do it. We are talking about putting a single ball in about a 12" circle at 40 yards, on a deer moving something like 25 mph, also bounding up and down, while you are ice cold, and tired as can be. It's tough. I'm not saying buckshot would make it easy, but what it allows is again a gun that is made for such shooting, making it easier on you. On top of that, buckshot itself, provided you did homework, allows you to be off by even 24", and you will still put multiple pellets in a vital.
The other thing buckshot does, is it hits multiple things at once. The problem people can have with buckshot is they are relying on one golden ball to find a mark. That's wrong. Buckshot is shot, for shotguns. Treat it the same as you would shooting ducks or geese. If you choose the right load, you can have multiple pellets in the lungs, and some will probably find the shoulder, spine, neck, or other vital part of the deer too. Some dedicated buckshot hunters shoot deer at the base of the neck, because it is the least moving part of a deer, plus you are putting pellets in the most incapacitating area of a deer.
So there is at least 3 scenarios that I find myself in most years that buckshot no only would be the best tool for the job, it would mean success over failure. Buckshot is a specialized tool, for a very multi-purposed weapon. Would I use buckshot for deer hunting here in South Dakota? Heck no. Everything is so open, and shots can be long. Even the tree lines, or tiny patches of what I can barely call woods do not grow the low brush like in MN, grass dominates here. Would I load buckshot if I were to hunt over an open field or food plot? No, shots in those instances or so easy, why would you?
And that bit about buckshot being a crippler, that's nonsense. A person could definitely cripple a deer with it, but that's no fault of the ammo. Even 4 buck will fully penetrate large deer at reasonable ranges under 40ish yards. Nobody doubts the power of a shotgun slug or ball, do they? Well I grew up in slug only country, and guess what? Most of the wounded deer were with slugs. Go up north, and most of the wounded deer were with rifle bullets. Should I even mention the thousands of deer poorly shot with a bow and arrow every year? I guarantee more deer are poorly shot with arrows than any other hunting method. I may come across as heartless, but I really don't care. I do care about wounding deer myself, but I do not care what others do, that's for them to live with. I see reports online (key word) of all these deer running around with bullet holes. You know what though, in all my life, out of I couldn't even say how many deer, my family has shot ONE deer that was previously wounded by a bullet, one hole in the leg, and it probably would have lived without suffering, had my uncle not put another slug through both it's lungs. I did one time see a doe hobbling, that I suspect was shot above the spine, but never could confirm it. Other than that, by a HUGE margin, deer are wounded by cars, not bullets, arrow, or buckshot.