My reasons for taking notes is basically "yes" to everything you mentioned.

Recently, my notes came in handy when I finally submitted my project as a final project for an online course I was taking. It spanned about 4 months of start and stop progress so a lot of my initial thoughts would have been lost if I hadn't journalled about what I did on days I worked on the project.

In my last job, I would take notes of what I'm doing by hand. Or sketch out plans of what I want to do with the internal tools I made just so I'm not wasting time or falling into the trap of feature creep.

I also do it to practice writing.

I've done most of my note taking in Obsidian.md (and I sync them with git), but sometimes I leave notes in a private Discord server if it's something I want instant access to.