Hi Dixie abd GreatJim
i think you're both right.
Music can be useful to learn English - in it you can analyze several grammar structures, enrich your vocabulary, learn about common or particular phrases. I find out it is useful especially thanks to the rhythm, and rhyme, as in poetry.
i must also admit that you can not make music as a starting point to learn (and to teach) English, at school.
Our duty is to teach the language starting from a standard basis (as we do for italian), helped by specialized text-books.
If we keep faithful to this reference point, then we can add examples taken from several sources such as everyday life, press, poetry, music.
The fact is everything is useful to learn a language. I depends on what you consider as the best way.
In my opinion (led to it through experience as an ESFL) is to overcome a certain shyness, a psychological difficulty, when someone has to speak a language that is not his/her mother tongue.