What? They want one to pay for learning vi/vim? I think, it should be the other way around, that is rewarding ppl for choosing to learn it and keep the knowledge active in their memory.
Especially true now, with so many reasons not to use it AND the sufficience of :help and vimtutor for the rest of the reasons.
I find that the best teacher in this case is a necessity. Find yourself on a basic command line with no nano or the likes, just good old vi, not even vim. Then go on with that important mission you're on! Traumatizing? Yes, but a chance at adaptation too.