They may be less traditional but they are not at all new, vertical grips very similar in geometry to the ones you are referring to have been the norm for various uses for more than 50 years. Sporting clays and FITASC shotguns have very vertical grips, both of those games are shot from a low-gun position and it doesnt hinder a good mount. Biathlon rifles have very vertical grips, and involves shooting offhand and unsupported. Everything from AR's to tactical and turkey shotguns have very vertical grips, very little of which is designed around shooting prone. The more vertical grips give you better control of the gun, aid in handling recoil, aid in a good trigger pull and put your hand and body in a more natural position. I dont think I would want one on a 6lb hunting shotgun that I'll carry one-handed as I part brush with the other, but that may be my aesthetics talking as much as anything. Aside from that I can't think of any use where the grip is anything but a functional benefit. Aesthetics/habits may say otherwise, but objectively I dont think there's any reason to shy away.