IMHO, music combines and develops:

--gross motor skills
--fine motor skills
--creativity / interpretive skills / intuition
--history
--perceiving and using part/whole relationships and abstract form
--emotional awareness
--awareness of/ quantification of time

(and probably more)

All the arts are good for this kind of multifaceted learning. But I think music is especially nice for its mix of abstractness and concreteness.

DeeDee