I'm curious if others can reproduce this for themselves?
My hypothesis is that the visual areas of the brain can get involved when the eyes are closed, and can pick up and interpret the proprioceptive information spatially. It may be that it's always happening, but that the "image" of one's hands is swamped by visual data when the eyes are open. Another hypothesis, I suppose, is that the visual expectation of the hands may be registering or, rather, its absence. You're "seeing" the expectation of the hands that should be there, but are blocked by your eyelids.
I should say that the sensation of seeing the hands is pretty fine, extending to the motions of the fingers. That said, it's easy enough to lose the image or forget it is there.