There are two schools of concept art. In one approach, the art is mainly a marketing tool and is there to sell your game to the publisher (not the audience).
In the other approach, the one I prefer, the art is mainly a discovery tool. In this case, the artist and I aren't looking for a cooler-looking "pistol" (it doesn't actually shoot), but one that's closer to the game's lore (the item is a few hundred years old, hence wear and tear).
(artist: Katarzyna Odrobińska https://www.artstation.com/katodrobinska)