There used to be a T-shirt as well as credits. I gave loads away and the last dozen went to a charity shop --- I think they must have got smaller while sitting in the wardrobe. I've still got a selection of stuff won --- even though the game was/is more important than the prize, winning "something" other than credits (which is like being given a bit of a new player) always felt good.
And I will forever believe that bringing back a Runners-up cup and/or a credit prize for 2nd place would increase interest (for established players as well as Newbies) --- though I think the game will just die before GG ever considers that.