Students need help with their dancing. Being able to identify a waltz (oom-pah-pah), or a Sarabande (slow, in three, and 'sits down' on the second beat) from their distinctive rhythms and texture is useful in itself, but there is an added bonus.
How is dance music useful to the music student?
From the Renaissance, to modern times, different dances were popular at different times. This means that knowing what type of dance it is, can help one to identify the period it comes from. Very useful, if you need to need to tell Baroque music from Romantic.
Rhythmic forms is the official name for dance music in music theory.
I have written a guide with musical examples, and posted on my teaching web site:
Listening to Music with Understanding - 4 - Dance Music
I have also posted the link to the download on the resources page for aural training of my teaching web site.
Image credit : Waltz at the Bal Mabille, Avenue Montaigne, Paris by Vernier, Charles (1831-87); collection Musée Carnavalet, Paris.