Why do all female celebrities seem to love pilates?

[No1]

Low impact, which will not give them any injuries as long as they listen to their (hopefully competent trainers), focuses on core strenght, which is benefitial for idols, great for toning and maintaining weight (not so great for losing it though), while also meeting in the middle for weight training (using your own weight) and cardio (you have to move a lot). It's a pretty balanced form of exercise.

A "normal" person should ideally be doing more than just pilates, but celebs, including idols already go through an exercise regime with all the practicing and moving around they do. I assume actors have a regime of their own, with personal trainers and stuff, so a few hours a week in the machine only helps them maintain their physique.

A lot of people find the repetitiveness calming as well.