I've noticed as my burly man-hero trots around Sanctuary he has the tendency to mash lesser critters under his magically embued footwear. There seems a very large number of snakes, scorpions, small spiders, and similar vermin that are affected in this way. Is this just sort of a mini-easter egg, or is there a benefit to do it? I could easily focus on more squashing if there is a reason to.
No, benefits, no achievements,nothing. It's just a "bonus" that was present also in the previous game (I don't remember if it was in the first Diablo too).
As Sorean said, "they make an awesome squish sound".