Is ballet a good exercise?

Yes In Moderation: Moderate cardiovascular exercise is good. But as with anything, extremes can be problematic. Performing too much or too strenuous dancing can cause joint and muscle problems. But again, exercise in general is a good thing for everyone.

It can be: This is why many forms of dance have become very popular practices for exercise. It involves an aerobic component along with significant muscle control and many positions require significant power/explosiveness.