You are right. I used to use them but pressing Ctrl was a pain in the pinky finger. :sp and :vs is 2 more keys to press. Using Space as a leader makes everything available at the flick of my thumb. I rarely ever move my eyes to the command pane.

I forgot to mention that I have mapped Space+P to CtrlP fuzzy finder. That too is a one pinch like operation, even though it requires two keypresses.