I do not use self-checkout for several reasons, including what other people have said: i don't get a discount, it's taking someone else's job, it's annoying as fuck. Further, I use my own canvas bags, and that machine yells about the weight mismatch no matter what I try. I'd rather listen to nails on a chalkboard.
But i also shop for groceries 1 time per week, which means I'm buying beer, which means the self-checkout STILL requires somebody to help me. I end up standing around for longer than it takes to go through the regular line.
Anyway, the self-checkout lines generally see very loud usage in my NC town.