Doesn't work when you're in palace of the dead and have no healers, doesn't work when you're in an undersized duty solo, doesn't work in frontlines when you have no healers. Situations where you have no healer are becoming more common and in these situations living dead might as well not exist because you can't use it without dying unlike a WAR or PLD.
Basically this.
If you want to use it as a dps increase then why not? It's only 10 seconds and risks death. Compared to fight or flight and berserk which are 30 seconds and don't risk death. It's really not worth exploiting in that way and it's not gonna suddenly make DRK solo the world.