Cost/ benefit analysis of "enrichment" activities for different ages for kids who go to preschool

Kind of the title.

My kids are currently 2.5. I'm looking at some of the different toddler and preschool classes that are offered through our rec center and elsewhere, because the new catalog just arrived. (Gymnastics, dance, soccer, languages, art etc).

They currently don't do any of them but part of me thinks kids would enjoy something like that.

The other part of me says that they have a lot of socialization at daycare and I'm not sure that it would be worth the hassle of trying to figure out how to get them to a ballet class or a music class for a 30-minute slot. (Plus the money...)

Did you do any sort of enrichment activities with your children? Was it awesome or did you regret it? Any other tips or tricks? At what age was it useful? And at what age was it not so much?

For what it's worth, I have boy/ girl twins so I could theoretically put them in the same class which would be easier or put them in a different class which they might either really like or really not.

Thanks in advance for any advice or tips. I can understand stay at home parents wanting to do all of the things because they're home with their kids all day, but I'd like to hear from this demographic of kids who have daycare all day.

This is the spring/summer catalog so it would probably be three by the time they started some of these classes, but the sign up is now.