For learning, I find LLM's helpful as a knoledgeable "tutor" or "friend" during the reading of a complex paper or book. Before, when I got stuck, I spend lot's of time going around different books/pages/papers until I was able to find a simple enough explanation that allowed me to "catch up". Now, I can ask the LLM and then continue from there.

Learning from a book is still the best... Although I have been told that learning a complete subject from a book is now an inproductive use of my time... Perhaps they are right, but I still do it.