It is a freaking good idea. I'm skimming the Vimeo Music Store FAQs:
You can get a music personal license for non-commercial and personal projects or a limited music commercial license for ad supported web sites, advertising a product or service or you charge viewers to watch the video.I'm skimming the FAQs but you should read them before you use the service to make sure that you stay out of trouble. You are buying a right of usage, not ownership.
I'm always up for a new tune so I'll be checking it out.