More portable #retrocomputing philosophizing: Whether a machine has "Instant-On" makes a huge difference in the tasks it's useful for. By this, I mean whether the machine returns to the same program and screen where you left it, when powered back on from inactivity.
Without "Instant-On", the machine demands to be used for long sessions, (else the boot time is too inconvenient) and demands your constant attention (else the power draw of leaving it sitting around powered on is wasted). Using the machine involves clearing your schedule and devoting yourself to it, like reading a book.
Examples of machines without "Instant-On": DOS-era laptops, #Book8088, #GameBoy, #MailStation.
With "Instant-On", the machine is useful for PDA-style quick jottings, grocery lists, etc. It is also useful for fun activities even in circumstances where you are likely to be interrupted.
Examples of machines with "Instant-On": #HP200LX, #HpOmniBook, #PalmPilot, #PocketPC, #TI92 (and other TI calculators), and, of course, smartphones.
While machines in the first category may offer a more immersive experience, they are far less useful to me than machines in the second category. It's like the difference between a luggable and a true mobile computer.
