Typing in LaTeX is way slower than writing by hand, especially equations. Charts and graphs are absolutely needed in many fields, and even though there are ways to produce them digitally, none are as fast and easy as taking notes by hand.

You could argue that teachers will just hand over PDF notes, but actually writing them yourself is a way better way to memorize them.

To this day, I always keep pads of graph paper on hand to jut to-do lists, solve equations or draw quick diagrams.