A small mission of harmless-looking little aliens comes to Earth to observe the place before destroying mankind. These folks have no music of their own but when they are exposed to ours, they love it. This hidden value of humans averts the harsh decree. The world is saved. As I recall the story is told in a humorous or ironic tone.
Story appeared at least 30 years ago. I wasn't a magazine reader, so it must have been in a paperback collection.