We already trusted our virtual life to google (emails, what we do, etc). Are we sure that we are ready to trust our real(physical) life too?
Don't get me wrong... It seems like a cool project but I wouldn't use it, maybe I am getting too old :/
So that's one possible future. And the tech they're developing is pretty agnostic to whether the information it collects is stored in the cloud or just on the device, so let's try not to be too pessimistic about something cool just yet.
What I wouldn't trust in this future is the Government to have easy access to this data, to see everything I've been watching and doing, and passing new laws to access this data even without warrants.
To me that's orders of magnitude scarier than a company using the anonymized data to send me more relevant ads on web pages, on which I'll probably still be able to use Adblock.
Privacy would have to built into the project on many layers. Without a push to do so from above, they won't.