During my physics undergraduate, it was for two primary reasons

1) Writing is more efficient when taking notes in real-time for maths notation

2) Better rentention of knowledge from the act of writing vs typing

Now as I teach, more students use tablets to take notes. But they're still writing, not typing

I disagree and am not sure what you mean by "efficient". I have never liked typing notes, be it in school or at work. Handwriting flows much better for me and I also find reading through notes, or just finding them, on paper easier.

I still usually show up at meetings with only a notebook and a pen... (added bonus: no-one asks me to connect to Teams/whatnot because they have a problem)

Many claim that writing notes by hand helps in retention of the material.

- Fewer distractions from other things on the computer

- digital becomes harder if you want to sketch things or write formulas (some friends in uni could type LaTeX as as fast as the lecturer could write on the blackboard, I certainly couldn't)

Efficient for what, though? It's certainly faster for rote recording of information, but I learn complex information in less time when I hand-write it out. Also, you have to be really well-practiced in LaTeX math packages to type arbitrary math well. Hand-writing math is much more straightforward with limited learning time.

I write notes when I want to retain the information in my head.

I type notes into my "second brain"[1] when I want to be able to later refer to that information but not retain it in my head.

1. Currently, a Markdown file in Obsidian.

It depends on the topic. Math notation is a 2D horrible domain specific mess, and it's much faster to draw it in 2D than forcing it into a 1D symbol chain. (Bonus point for Greek letters or $\weird$ symbols.)

When studying CS questions for software engineering interviews, I found being able to sketch and freehand draw helped me understand concepts such as memory, cpu architecture and recursion better

Absolutely not more efficient when dealing with Mathematics or math-heavy notation which is 90% of my notes. Maybe an iPad might help but it's out of my budget right now.

Why at all? If you want to record the lecture, use photo, video, audio recording.

Citation needed.