i have grips like that on 2 of my ar's.
i really like them, when shooting rats, if it moves and you have to relax, just let the side of your hand rest on the bottom plate, when shooting, you don't really have to grip the grip, again lay your hand on the bottom and use only your finger to pull the trigger. the same with coyote calling, work the call with your left hand and stay ready with the right resting on the shelf.
that style of grip is really handy and hand fitting , at least to me.
different grips for different folks.
chose what fits you and what you like.
