> Doesn't the lecturer give out notes ahead of time?
Sometimes. But the thing about taking the notes by hand is it fixes it in your memory. Glancing over pre-printed notes just does not work (at least for me). I still have the pre-printed handouts on Special Relativity from Ph2, and I never quite understood it.
It's sort of like reading a programming language spec. I think I understand it, but trying to implement it shows I didn't understand squat.