Again, let me say they are un-naturally inconducive to good aim. Do yourself a favor... if you know someone who will let you try, you will soon understand. Hold one in the store. You’ll find your grip hand will be against the side of your belly. When fired, it often kicks your belly and it is painful.
I think any shooter used to an AR or AK pistol grip are going to be able to control a shotgun with a pistol grip. If you are holding a shotgun by your side to shoot it you are doing it wrong.