the problem with Reactor Cool is you cant stack it with Cocoon, you waste 5set points and get int/mnd from it. also it doesnt make any job triats and it doesn't last very long.

it would be more efficient to use Mind Blast or Frost Breath (especially if your tank build includes HP) for paralyze. if only for cocoon, although you can argue its use inside abyssea or if you already have capped def over the monster. (personally i dont test for those things so cocoon makes my life easier.)