Originally Posted by
Risvertasashi
As an example, one of the savage raid bosses, Guardian, will target a DPS player for a burn and/or bleed type DoT attack with ticks that are very strong. SCH can simply have the fairy use Fey Union (perhaps on top of Whispering Dawn as well), and that mechanic is handled. The SCH (and his/her cohealer) can then DPS, or heal the tanks, or whatever else as needed.
In comparison, Noct AST would have to use GCDs and spend MP to accomplish the same thing. The whole duration of the DoT, and possibly some extra healing to top up after if it's immediately followed by a raidbuster. A considerable amount of MP for a single target shield at that. (SCH's shield is even more expensive, but SCH has the advantage of having more tools to work around it).