If your everyday activities sufficiently interesting to bother spying on, then someone will find a way to spy on you anyway. If they aren't, then I doubt anyone will ever bother to sift through the data to find precisely when you went to the supermarket.
That would probably be true if sifting through these data were a very complicated and thus costly thing to do. But is isn't, especially since you can more or less to it for all of your targets simultaneously. And there is good reason to do it, too: profiles of people are a valuable resource.
