Sure. But it’s a lot easier to learn nonlinear mathematics or quantum theory with a textbook than without. In this case you’re not learning about “what is a for loop”. You’re learning “why a OnceLock here rather than a RwLock”.

Many of us work on teams so we already have to deal with the majority of code being written by someone else. I’ve got code that’s more than a decade old, written by people I’ve never met.