Not really, though. If, for example, I could pinch to zoom out of the text, identify the parts I'm interested in, and zoom back in simultaneously on two differe

Not really, though. If, for example, I could pinch to zoom out of the text, identify the parts I'm interested in, and zoom back in simultaneously on two different areas of the book side-by-side (using both hands, say) _that_ would be superior to what I can do with paper now. And much more convenient. I don't think it's impossible to do with software alone; quite a small leap for something like onenote today. The problem, as the top comment notes, is the way everyone treats text as purely linear.