I'm mostly joking but I just think the Precure series has much more going for it's characters, music, and most of the Precures plots are interesting while Aikatsu just didn't hit with me for those same things. Though I still enjoyed it for the episodes I did watch of Aikatsu.
Precure is a magical girl anime and has a lot of sequels and spin-offs.
Aikatsu is based on a trading card game with idols which got anime adaptation in same time with a lot sequels and spin-offs as well.
You might don't know about them because they are shoujo.