Quick Hit Versus Doublecast

I see Quick Hit as the recommended method of dealing with basically everything late game in Final Fantasy X.

Why isn't Doublecast ever recommended for dealing with anything late game?

EDIT:

Doublecast is Rank 3 and Quick Hit is Rank 2 (on the remastered versions of Final Fantasy X.)

This means that you can get in 3 spells to every 2 attacks. Presumably every attack does 99,999 damage late game, so it seems like Doublecast would be better.