If he was honest with himself, he would rightly say he did those things for his own edification. If you have the time and ability. As someone who also cares deeply about his craft and spends more effort than I probably should improving my personal tooling, I'm clearly all for it.

Is it strictly necessary? Most certainly not. I've met equally dedicated and talented individuals who are fine adapting to existing tooling and working around idiosyncrasies rather than improving the tooling. That personally drives me batshit, but I can stomach it if required.