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

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).