See
this from a Library of Congress link on Edison's thoughts of possible use for his new invention. I find it rather amusing and ironic that the use as a music reproducer was originally not considered worthy of one of the top three spots.
But from these quotes, he must have changed his mind.
"Just because something doesn't do what you planned it to do in the first place doesn't mean it's useless....
Of all my inventions, I liked the phonograph best...." Don...