I did the same, but the only thing that happened was that I couldn't type symbols (quick, type a $ without looking at the keyboard). I exchanged it with one with keycaps afterwards.
Probably. I've never measured them specifically. But since I can 'just' type them without looking or frequent mistakes, I'm probably faster since I never have to stop and look.
I've been using a glyphless keyboard for about 2 weeks now (accidentally) and I have definitely gone up in accuracy. Now I can hit $&% in the second try