Lani seemed to have the potential to be a really interesting character, especially given her past dealings with Amarant. But like Spatvark says, she's effectively a throwaway villain who hardly features.

I like her 'hidden scenes' with the Moogles at Madain Sari (accessible during disc 4) and her cameo during the game's ending - but I had to watch the ending twice before I could be certain it was actually her.