Math shows that chatoyant starts winning around ~42% (or was it 46%) cure potency. Obviously you use what you have, but there's a big difference between Abyssea and the rest of the game. No one is saying that SCH is as useless as RDM, but the things it supposedly does well like healing and nuking are irrelevant to current endgame (for the most part). Other than embrava and stun spam which any abyssea burned mule can do, SCH offers nothing. This is a problem with mages in general, and isnt specific to SCH. The things that make SCH unique though are underwhelming to say the least.