Dancing is basically a form of arobic exercise. There are plenty of benefits you get from arobic exercise because you are working the whole body while doing it.
If your looking for a more break down of what muscles your working or what fat your burning I would suggest searching arobic exercises and benefits.
I taught dancing for many years to young and old. Older people needed the dance exercises more for therpy and told me it really helped them overall with their health. Young people told me it helped keep them in shape and was more enjoyable than going to the gym everyday. So dancing, if done correctly, is an exercise.