The medium is the method
Jeff Hawkins, founder of Palm Computing, from Designing Interactions by Bill Moggridge:
I think paper is just this wonderful medium; it’s been honed for a thousand years. It’s really great! To try to do what you do with paper, with just drawing—line width, sketching, and so on—it’s very hard to get a good experience. Where the tablet type of computer really shines is where you’re not trying to capture the paperness of paper, but you’re trying to get the electronic or the back end of it. Form filling is a great example, because actually forms are pretty hard to do on paper. You never have the right space, it’s hard to know where to put things, there’s not enough room for instructions. So, there’s an example where an electronic version of a paper equivalent would be better. But in terms of the general idea that I’m going to sketch, draw and have a free-flowing paperlike experience—I’m skeptical about that.