I wax by big toe because it has some hair on it (the others have hair too but it's so fine you can't see it)
I actually find that quite a few people shave their toes/top of foot. I come into contact with lots of feet being a massage therapist and I notice stubble on quite a few feet so it's not that uncommon.
I have a few follicles of very fine hair on each of my big toes. I know it's there and it bugs me, so I swipe a razor over my big toe every day in the shower when I shave my legs. I haven't even seen any stubble in years because I'm determined to keep it completely at bay!
I've never even thought of that... Well the hair on my toes is so light and fine that it's not noticeable. I guess some other people have darker hair, so it shows up more. The same with arm hair. I don't shave my arms, but I know some people who do. Mostly because their hair is thicker and darker in those areas.