Is Dungeon XP really that bad?

[Tsukino]

How does this work? i see people asking for fate groups and when i joined one i gained no more XP for completing it? and most of mobs were already tagged so i gained a pathetic amount of mob XP, is it really worth grouping for fates? for some mob xp? i never seemed to gain much at all by this.

You get the same EXP for completion, but you get EXP for every enemy your party "claims" (name is red instead of purple).