Desperation is such an easily accessible skill, I think it would be a giant waste. Even with the worst possible IV there is probably still a use for her. I have a -Spd def+ Bridal Caeda and she still kicks ass because she survives Ryomas farcounter, while Linde doesnt.
In my entire playthrough, I have encountered an entirety of TWO Shannas. With both of them dead, and having an S Class Blue, with a S+ waiting at 4*, I don't know how much ill be summoning for blues after this banner... maybe if they bring Azura back... Then again, I don't like using messed up IVs (Perfectionist thing). I'll be keeping her, most likely not using or training her, maybe ill get another Mae and fuse them.
Pokemon GO
Fire Emblem Heroes
Fate Grand Order
Dragonball Legends
Dragalia Lost
IV Calc
Heroes