> are there people that use the caps lock key?

I for one do. Old habit when typing in longish C constants (ECONNRESET) or shell environment variables. I'm used to typing capitals by holding the Shift with the pinky of the other hand than the one entering the letter, so with long strings of capitals sometimes I'd have to switch for every other letter, which gets old fast. With Caps Lock, I press it, type in the letters, press it again.

Completion mostly works these days if you have it, but you don't always.