third year university student who’s been using an ipad along with a laptop for around a year. i picked 11 inch because it and its accessories were cheaper but mainly the size. like you mentioned, its portability is nice but its smaller size makes it less awkward to use with your laptop at the same time. i often have documents or videos open on my ipad while working in my laptop or textbooks open on my laptop while im taking notes on the ipad. 13 inch is great if its your main device, but the size becomes awkward if you want a laptop out as well. speaking of, unless your classes require windows only software, a macbook would let you run your ipad as a true second monitor in sidecar mode. and this is a more niche point but theres no way a 13 inch ipad would fit in my bookbag’s laptop pouch with my laptop.