and perhaps skull sales but besides that
Skulls are important to some of us! Those that don't sell have scientific value, unless there's a big hole in it!
I haven't head-shot a critter in a LONG time. Cheapy 22 solids are what I prefer. I get an exit hole most of the time on coyotes and lynx. So what - it's a .22 hole! I don't bother to sew it up. I've been carrying a 22 Hornet lately, and shooting trapped critters (mostly wolves) with that. It works fine as well, but a couple stitches are sometimes required.
Paper towel in the hole(s) before you try to haul your critter off saves some leakage, sometimes.