Lets discuss luck for a bit. It seems to change within games. I know a lot of people here have played a lot of final fantasy to know the difference. In case you don't know or recall I simplify it for you.
Luck did not appear in every Final Fantasy
FF1 - was suppose to be used for running away.
FF7 - To me it acted as evasion.
FF8 - critical hits, and item droppings.
FF9 - chances of status spells success
FF10 - Luck in this game, according to FF-wiki strengthened critical hits, item dropping, and evasion.
So what do you think is better? I prefer it being an evasion. I guess Critical its is more understandable. Running from battle to me was a waste.