I must say I have never used the feature - my main thought being that if the pictures in the public gallery are not enough to go on, I will just move on the next profile. I'm a bit stubborn like that and don't want to spend any money rewarding crap profiles! That and I don't really want to start paying out for Adultwork credits. I have been more tempted to pay for the PG a little while after a good punt (not too sure why, maybe to remind me of it I guess) and if I could pay for it with paypal, probably would have done.
That said, in general the good pictures are non photoshopped pictures with a face. A photoshoot can be nice but the heavily photoshopped photos start to all look very samey, where the models look a bit like plastic manequins and don't really give much of an indication of what the girl actually looks like .
Also, not all "no face shots" are created equal. In this specific example I would say some of the ones on Kitty's profile are enough to go on and you can kind of tell what she looks like.