Being uncaballed has two big advantages, one is that you get to pick your enemies/allies a lot more selectively - Imperial thief probably does not want to be enemies with Battle duergar, but will end up fighting in some cases. Two is that you never have to retrieve or defend in bad situations - the worst is when you log on without the item, there are defenders, and you know that there's a small but very real chance you die but you have no chance to actually kill them, and that if you don't try and retrieve it's going to reflect really badly on you.