Its just an indicator of class, just a little obscure item that tells you the class without messing up customization a ton, like a shirt that says "Medic" on it would.
I know what it does. I read the thread on the SD forums. It's just not what I expected; which doesn't mean I dislike it very much.
Giving you a Shirt with "Medic" writing on it is entirely different, though.
The gloves tell you - the player - what class you are at the moment.
The shirt would tell others - your team - what class you are at the moment.