> As for the usefulness aspect, personally I am not sure that this has a benefit over e.g. watching youtube tutorials/following books.

I do like YouTube video tutorials, but only as long as they're short. Watching Handmade Hero (by Casey Muratori) for example was a little frustrating: the videos are long, the codebase is large, things are moving fast, and I'd get lost.

I often wished I could pause the video to look up the definition of a function, or get an overview of when each file/line was edited and jump straight to that point.

Books/blogs are ok for explaining large codebases that already exist, but not for following a project as the code constantly changes. The book Crafting Interpreters did a really good job there, but that's really rare and hard to do.

I think CodeMic could be useful for this kind of long-form tutorials.