The other thing that scares me about the optimized storage is the privacy concerns. Has everybody forgotten about "the fappening" stuff?

Now imagine that your PC backs up stuff to the cloud without your knowledge. Not only that, it will only backup those old files that you forgot that existed.

Maybe I'm being overly paranoid, though. I guess that a nice interface that only starts the backup after a prompt and that shows what files are being backed up can help a lot.