If this will run iPhone OS (or something like that) and not full Snow Leopard = FAIL!
If it will run full Snow Leopard = Could be interesting. (And of course it just gotta have built in 3G).
I think it's more interesting than that. If it does run the iPhone OS (which it probably will) it will probably serve as the underpinnings of the iPhone OS. Multitasking, API for developers to talk to other apps, and file structure.
I don't see a reason yet for me to buy it, but I am excited to see what they can do and how this will influence the iPhone. Any serious change to OS Touch would be held off in order to introduce this product with all the new featurers.