If I didn't want to do cloud sync, I'd be more excited about a local sync. One doesn't tend to generate gigabytes of data on a phone so even a Bluetooth sync would be sufficient for most people.
You don't use your smartphone to capture HD video, do you?
I do from time to time. Even they can be transferred over today's WiFi in a matter of seconds. My point is that keeping local devices in sync for all but a very few uses is already today easily solvable. So I wonder why we'd want to move to an architecture where our computers are reliant on our phones... there seem to be some significant tradeoffs to that model and it's not clear to me what real gains there would be.
>keeping local devices in sync for all but a very few uses is already today easily solvable.
No, it really isn't. Manual file transfer is... doable, but still more problematic than it should be. But there is absolutely nothing that will seamlessly keep my phone in sync with my tablet when I don't have network access (i.e. I take a photo on my phone and it's on my tablet, without me doing anything). If you have a solution, link please.
Notice that no one is saying that a secondary cloud-tier is excluded from this vision...