If you think about what smartphones are really most like, they're basically pocket-watches: big flat things with a metal case and a glass face that you flip open an optional protective cover to look at, which sit in your pocket when not in use, and trail a cord out of said pocket to somewhere else on your person (your ears, nowadays.)
That said, the word "watch" is likely a very good word to keep for the wrist-devices: their natural UX, given the limited possible set of affordances, is designed around passive alerts. Which is to say, they watch for events, and you watch them.
Great analogy. Just enormously big and inconvenient pocketwatches with a lot of complications. (/me wearing wristwatch and a SonyEricsson W580 in my pocket)
That said, the word "watch" is likely a very good word to keep for the wrist-devices: their natural UX, given the limited possible set of affordances, is designed around passive alerts. Which is to say, they watch for events, and you watch them.