We care about it when blizzard is nerfing other classes because of PI. Apperently (By Kalazami) demolock just got a nerf because of the existence of PI.
I do not care at all about PI. It sounded like something fun to coordinate with another player to burn something fast down, or do a ton of aoe damage. But blizzard seems to care. Those nerfs are really awesome for demolocks who do not have a priest available. Well done blizzard 