I don't really see it as worth it. Tidus does just as good a 99999 to the majority of enemies in the game with just Excalibur. I don't see it happeneing against Nemesis when I get to that point, but still.
(an even mix of 45/99k with blitza ace against shinryu isn't bad in my book at all though)

Of course when I randomly go and race chocobos and actually get 0:0:00 I might be singing another tune, but I don't see that happening^_^