allow us to skip quests that dont really lead to anything but killing monsters for rewards, so if u cancel aa quest you no longer get the quests that would follow on from them without it costing reals to skip - much like what you can do on the join dragon eternity FB page by cancelling the quest

Of course there are the quests that you cannot skip like - creating boots, Skrag Caves, Dragon ones, but there are just too many quests to do to get just rewards for effort put in