Some tech writers have made this point already, and I probably won't get it out as clearly as they have, but the problem with smartwatches and our perception of them is that we're thinking about them in the here and now, and not in the future. Microsoft (well, Ballmer) famously laughed at the iPhone as too expensive and useless before it took off and crushed the Microsoft Mobile business into dust. He was thinking of the here and now, and not the future.
This is where Apple's so-called fanboys can be used to bootstrap a tech shift that would've taken much longer otherwise. When enough people start wearing these watches, they'll start to have more applications. Apple Pay will work with the watches out of the gate, so the people that (legitimately) complain that the phone is just as convenient as pulling out a wallet will now have to re-examine the position. The phone is on your wrist and is unlocked by being there and tethered to the phone. (Presumably, one day you won't need the phone at all, but we're not there yet.) And if you can trust your payments to your phone/watch, you can probably trust your car, computer, office door, etc., to that combo as well.
Without Apple, there's more of a chicken-and-egg problem. Nobody wants a watch because the services don't exist, and nobody wants to make a service because there aren't enough watches out there. Get a few million Apple faithful to buy a watch, and suddenly people that are a lot smarter and more creative than me will be making services that can interact with it.
I don't know if this market has legs—I can easily believe that those are things people will shy away from as too insecure or too cumbersome or too ugly. Having to charge one more device every single day doesn't really appeal to ME much, I admit. But if I try to think about the smartwatch market and how it might work in the future, when a bunch of these concerns are addressed, I can see there being somewhere for it to go.
(As to your comment about tablets, my iPad 3 is my most used computing device. I happen to be sitting at my computer right now, but this is the first time I've made a comment on /. from my home PC in months. I bought it originally to give me less of a reason to buy a new phone, but the unexpected side-effect is that I don't really care about home desktop computers anymore either. I'll upgrade in a year or two, when it stops getting OS updates.)