Her isn't, but I never said you shouldn't get her. If you don't, and should playing FF all together.

to use espers just select magic then press up until you get to it and gogo is far from useless as he can use every ability on the game(i dont think he can use gaus rages but i may be wrong.) + his own unique mime ability which is underrated by a lot of people because mime can do a lot of great things if you use it properly.
As I previously stated, two Bum Rushes.