It's not just about keeping people alive either. If, for example, a BLM gets hit by a debuff that interrupts pretty much every cast or slows/heavies him then unless the healer does more damage than the BLM it is better for the party's DPS that the healer removes the debuff than that he continues to DPS hmself. Sure, a lot of those are avoidable but if my healer plays with the attitude that if I make a mistake and gets hit by something then I deserve to suffer then I am going to find a new healer. I am all for healers doing damage but the MAIN point of a healer is to, you know, heal. It's kind of in the job title.