What is the Point of the Caladbolg?

[Skyblade]

It does, actually. Wakka's and Tidus' weapon deal more damage when they're at max HP, Auron's weapon deals more damage when he is at low level (the lower his level, the more damage he does).

Unless I am really misremembering this game, character's don't have high/low levels. There is no level counter, just the sphere grid. So how can Auron's weapon do more damage when he's at a low level?