I think your missing the "other" reason most folks pick revolvers when 4 legged threats are the concern.
Besides the added power rimmed magnum cartridges provide is the inherent ruggedness and reliability of the revolver.
Most cat and bear attack I've read about that involved a "live" person resulted in shots fired at "contact" distance.
Auto Pistol reliability has come a very long way but pressing the muzzle into a critter can push them out of battery and more or less, disable your gun. Revolvers do not have this problem.
Show me a professional hunting guide who packs an auto and I'll show you a green pea guide...