Choreographed programs may be easy to learn for the instructor but they don’t take the participants into account.
If you are stuck with one routine and your class is way under the level of that routine, what will you do?
I think this is the biggest issue with ZUMBA and CrossFit (and others). It’s for the instructor and not for the class.
Teaching you a “routine” is a huge money maker for ZUMBA and CrossFit but it does nothing for what a group exercise class is all about which is providing the best workout for those is your class, not the workout that have been designed by a Corporate Executive getting richer and richer by copywriting thier “program”
A seasoned professional will be able to assess their classes needs/levels and then design a workout that will be safe and challenging for the participants.