So I was in the team up and was helping a couple wizards in the mid 40s in a random casual dungeon in Dragonspyre nothing to big. (I was on my level 123 ) on one of the fights I said "I think I might need another blade to kill, in case the boss storm shields this turn" . The balance wizard I was helping did have a blade that would have helped kill, but she (rather selfishly) put it on herself.
Her reasoning is because "If we cast more spells we get more experience"
quests give experience, battle experience is not big enough to matter. (And she never did end up attacking just to be clear)