Yeah works great with Raging Strikes aswell, I somehow managed to use it, then spam Fire I and it bugged like i click it as often as possible so i lose the least time, but then the Fire I interrupts itself multiple times, which is hilarious in fact :P

But that buffs are delayed as hell is really good to see on a BLM, switching from Umbral Ice to Astral Fire and you can cast the first Fire I or Flare or whatever Fire Skill with 50% casttime still :X