I don't shoot snakes, unless I have to. (I hunt in Utah, Idaho, and Wyoming, though. We really only have to deal with rattlers.)
When I carry a pistol, it is for predator defense (big cats, bears, moose, and pot farmers). You can laugh at the moose reference, all you want. When an angry, 800 lb female decides you need to be dealt with (for whatever reason...), you'll see why I list them with cats, bears, and pot farmers.
Due to firearm and ammunition restrictions in Utah (where I do most of my hunting), it is illegal to use my pistols for small game, big game, and upland game species. They're just there for non-game encounters (again - predators, as described above).
I'd like to get into the details of nasty encounters with two-legged predators, and the awesomeness of wondering if you're about to get shot in the back (for accidentally stumbling upon a poachers' camp, or jackasses that just think they own the entire mountain for a week), but I'll get too angry thinking about hunts that got ugly.
The moral of the story is: Nasty encounters with two-legged predators are a situation where the enemy knows you're armed. If you can have the advantage, by having a pistol they don't know about.... you're that much farther ahead.
Lastly-
Every so often, I am presented with a shot that is so close I don't want to use my rifle. The velocity will be too high, and terminal performance of the bullet unsatisfactory (or just undesirable for the available shot). Having the ability to make the shot with a pistol is a nice advantage.