To be fair, I also use screens for at least part of four of those things (not counting buying books on Amazon, then it'd be all 5) and plenty of people also use a screen for books (even if you don't count e-ink, which isn't light-emitting so probably shouldn't count as a screen in this context). You can do without them entirely all parts of those activities, obviously, but it's less convenient and/or more expensive, and depending on your goals or workflow may be entirely inappropriate (some drawing/art, for instance).

It was a bit tongue in cheek, but it's not so much that I've forgotten about them, but that I think people giving this advice tend to forget that many folks just don't buy paper books, notepads to sketch or write on, pens and pencils, etc.