Sure. But I also am in university, where notes are distributed as PDFs, and I have e-books also as PDFs. It's much easier to annotate directly on a PDF than to have to print them, annotate, scan, and ensure the scan quality is good.

At some point, 'it's cheaper' is just not a good enough argument for paper notebooks versus the sheer versatility of an iPad.

I would have to buy a veritable cart-load of writing stationery to emulate everything I do on my iPad. It would likely still be cheaper, yes, but it would also be much more of a pain in the neck.