Learning CVS is not "diligence." If anything, it takes up mental space you could be using on things like remembering to bounds-check your array accesses.

Asking contributors to learn CVS as a quality gate is like having a tech interview process that requires beating the hiring manager at chess. Sure, you're looking for smart people, and sure, people good at chess are usually smart, but the correlation is so low you'll lose out on good candidates and get candidates who are better at chess than coding.