> I think this is a complementary thing for implementing B-trees or solving exercises. That is needed as well, but will you still remember the finer details of splitting nodes in a B-Tree a month later? Or six months later? Which might or might not be necessary.

This is a very good point. This is the type of knowledge which I don't care about retaining. I'm pretty confident that I can re-learn it in a few days when I need it later. It's also not critical to have this knowledge at the top of my head as I'm rarely going to be in a situation where I need to recall this immediately.

This is quite different from vocabulary where it is critical that you can find (or understand) the word in seconds otherwise you'll fail at communicating.