Interesting.
A little dish soap and water is how I clean my muzzleloaders, but I never tried it as a patch lube.
It seems to work fine when doing some target shooting, but how well does it work after the water dries out? How well does it work if your dish soap lubed patches are kept in a tin, or ready in a loading block for days at a time, or as I often do I have a small roll of lubed pillow ticking that I cut off at the muzzle when I load. I doubt it is going to work so well when the water has dried out.
I supposed I'm just going to have to try it.
Oh, edited here to include a comment about spit patches. Again, okay for target shooting. I sometimes do it that way myself. But, hunting when the gun will remain loaded for a long time, especially in freezing weather - I don't think so.