I do not use FaceBook; there are several reasons for this that I won’t go into here. I will just summarize it as Faustian deal, though FaceBook is only one of many such online roach motels. Instagram is another lovely.
One reason to embed a copyright into your images (as I have begun doing) is so that at least your name is visible when the image is stolen; the thief will have to at least take the time to edit out the copyright. In my case I was seeing a double theft: commercial web sites selling camera equipment using my images, but worse, they were using my server to host the images (too lazy even to copy them!), which was a cost (bandwidth usage) and performance hit. At least make the thieves work a little by hosting the image themselves and having to edit out the copyright.
In the case of FaceBook using images without payment, this might even offer a small benefit: your name visible in an image posted somewhere. Small consolation, but not nothing. Unless of course it is next to some offensive product!