Which as I said CAN be done on a Kindle You can write detailed notes and highlight and even write basic mathematical formulas. I never said you could draw pictures or intricate and complex mathematical formulas and neither did you in your example as why a textbook is better.
I haven’t change my reasons. I didn’t list everything one might want to do in the margins. That would take all day and cover numerous disciplines. A Kindle couldn’t do 10% of it. And what it can do is waaaay too cumbersome and a big waste of time in my opinion (because it is so cumbersome).
I’m sure computers will become much more capable in the future, perhaps even become a lot better for study than the old fashioned way of doing it. Then, I’ll gladly change my tune. But we’re not there yet.