My grandparents grew peanuts, and we would sometimes eat them raw (although people here call them "green" when they are unroasted.) Raw peanuts have a sort of grassy taste, very much like alfalfa sprouts. I don't think they would be good at all ground into peanut butter.
Also, as others have mentioned, they certainly can upset your stomach. For many people, more than just a few raw peanuts will do the trick.
But I do like raw almonds, and I think raw almond butter might be good. Very different from regular roasted almond butter, but not bad.