That it's useless against the target. There are way better options to use in PvP like corpse thrall when in a graveyard, or reanimate when out of pvp. Vampiric touch is better for PvE, like while in a pvp fight, and you need to heal, cloud lumberjacks are wonderful for healing up over a healer, but when you use it in combat, it doesn't seem to yield really good results very often.