They are helpful. But, they are of far greater value with modern centerfire guns than traditional ML'ers. With ML'ers, and particularly round ball, trajectories tend to rainbow after about 125 yards, making range estimation the far greater limiting factor to accurate long range shooting beyond that distance (particularly with RB's).
For hunting purposes what you're most concerned with is; "will the projectile be able to do its' job at this distance'? An additional item to think about is, beyond about 150 yards, most of us aren't able to use iron sights very well on critter sized targets smaller than a woolly rhino. It is the rare traditional ML'er that wears optical sights, though certainly there are exceptions (like the Whitworth).