This comes up every once in a while.
Shooting is fun. Buy some and try them out to get a feel for the pattern, spread, and reliability in your pistol.
That's the fun part.
During this, figure out the limitations. Snake shot is essentially a tiny shotgun shell. Those tiny shot pellets? Yeah, they don't pack much of a wallop because they're lacking in the mass department.
Shot works best in a smooth bore. Riflings screw up the pattern and spread. This means fewer pellets on target, as well.
So your range will be lacking as will your penetration.
For small critters at close range...probably meh-OK. And I mean close.
Now... the whole shooting sneks thing: do it if you want to, but the reality is a stick/pole is all you need.
Sneks don't chase after people. They fully recognize the size/mass difference ain't in their favor.
And if you're close enough to be in danger, the stick will serve quite well. Walking sticks when hiking are an awesome idea.
Most sneks are harmless to humans. They're harness to pets, too, depending on size. You don't have to memorize every snek to figure this out, either. There are only four venomous sneks in the United States:
Rattlesnake, copperhead, water moccasin/cotton mouth, and coral.