Completing the quest doesn't update your journal, or give you finishing experience.

I always figured that belt was the only prize deserved.

Considering that you can get smoked by 50 damage fire traps that level 5 rogues have difficulty seeing -- unless you metagame where the traps are having played the quest with a past character, I question the lack of exp given by this quest.

Yep! I just had this issue earlier today.

You are vastly overestimating the difficulty of this quest secutor. Noted, and it probably should be giving XP.