When you meet your first companion in the story, they are wearing a full set of gear, but as soon as they join you, they suddenly decide to strip off their gloves, belt, and bracers. This was originally done to keep their combat stats lower early in the game, but since companion gear no longer affects their stats whatsoever, excluding them does not serve a purpose. My understanding is it's simply a matter of equipping internally existing items, so please allow them to fully express their iconic default styles like all the other companions do by getting to keep their gloves, belt, and bracers!