I will sing the praises of git and vim, but I didn't pay any money for them. He says extract a commitment, not necessarily a monetary commitment; I read half a book before I started using git, and vim took a lot of practice. So you could use more specialized terminology or something like that. git and vim are both very well-spoken of, and I probably wouldn't have bothered to learn them if they weren't. But I also don't bother to spend money on things that don't have a good reputation, if I haven't had experience with them already. So, either way, requiring a commitment from the user turns away a lot of them.

(I've never read your website)