Not sure why you'd remember the ones you rarely need. I just memorized the things I use. Remembering stuff you use is much easier than learning a programming language. I've been programming for over 30 years and I've been using vim as my only "IDE" for the last 14 years. It would take me significantly less time to teach someone vim than to teach them programming.
See, the thing with Vim is that I don't actually know which of the endless features I need. I don't really feel like I'm missing much with the basic text editors.
Maybe you could shine some light on it for me? Right now I'm the sideways-glancing monkey meme every time IDEs come up.
For me it's just convenience. It's not because vim is better, but because it works on any terminal. I don't depend on a particular IDE setup, I can jump on any computer and start working. And since I've been using it for so many years I'm very fast in it. The best tool is often the one you know best.