Most PuG tanks won't be able to handle the enmity generated by it at the start of the fight.
Most roulette WHM I see won't bother with anything other than Cure 2 and Cure (in that order) while most story-mode WHM raiders I see won't bother with anything other than Medica 2 every 30 seconds without even bothering to time themselves with the mechanics to be the most MP efficient.