Lets hope there really are opt outs
I hope that I can opt out of having the sync work, since I have different requirements for different machines.
And I especially do not want the system to run a back up on my data. There is no cloud I would ever trust anywhere in which I would confidently leave my data lying about. Nor one that would leave my pictures in.
My computer is probably more hackable, but less attractive than the potential motherlode available in a cloud data centre. When my data and mail is downloaded and backed up at my end, and my pictures are backed up on a DVD stored in a separate location, there is some chance of hanging onto it. For now, I view undisturbed long term cloud storage as wishful thinking, and from privacy point of view, far too much temptation for various self-important and morally questionable authorities to keep their mucking hands off.