Yes, that keeps people from stepping on each others' toes, but revision control systems are really useful even for a single developer working alone, just to tra

Yes, that keeps people from stepping on each others' toes, but revision control systems are really useful even for a single developer working alone, just to track changes, make changes to try something out and be able to revert easily, etc. You can do all that of course by making a bunch of ".bak files by hand, but a modern revision control system makes it much easier.