Maybe she doesn't like the way her lower body looks, or something... Though I can't imagine it could be bad, given what we do see.
It is immensely frustrating when someone takes all photos in close-up, especially from that angle which tends to make a face look chubbier than it is. You even see this in so-called professional porn sometimes, where you want to yell PULL THE FUCKING CAMERA BACK ALREADY. I know this chick is only working with a shitty webcam, but still.