"Here's how to turn on a new feature whose settings your devices will magically forget for no reason once or twice a year, and occasionally lock your UI for several minutes while phoning home. Also make sure you replace ALL of your devices frequently with ones with the newest Android versions, because we're CERTAINLY not going to support this feature on anything older than the jar of spaghetti sauce in your fridge, which you'll find out when one of them just stops being compatible, which will happen at the WORST possible time when you're in an important meeting or having your last phone call with your dying grandma or something."
I really do like the concept in contrast to some other comments here. I think improved integration can be a path to a better user experience. However, I have doubts Google has the skills to bring it home and actually make it work correctly every time and across numerous devices. A project like these takes something Google doesn't seem to have: commitment.
I see this more as an idea that will come broken on delivery and then removed in the following major release. I'd like to be proven wrong. Really and truly.