INT doesn't help SCH because when you use Cleric Stance, your MND swaps with your INT.

So for SCH it doesn't help at all.

And no, Ninja isn't the only one with useless traits. BLM has a trait that has it so Surecast may come back instantly. Not that helpful, as most people, of they even use Sure cast, use it before a predictable hit, and there's not usually two predictable hits in a row