To counter point X, an off tank SK or Pally can use this to negate some nuke/heal threat and gain more power to nuke/heal longer.
Also I've seen healers use this very effectively in groups to have extra power at the end or enough left towards the end to make a difference. Most notably it helps negate a good bit of threat from AoE and large heals to make it very easy to maintain aggro for even inexperianced tanks on nameds. Not that I like my healers gettin that close ;) It just works.