I already have a max leveled Shuten, should I also raise swimsuit Scat?

From what I've heard Scat's AOE NP damage at np5 is only barely more than Shuten's at NP1 so she is technically an improvement for strictly AOE farming but if you get NP2 or higher Shuten's farming is better and Shuten's kit in general will be a lot better.

Why wouldn't you?