Whether I actually use the downloads or not, it allowed me to discover new bands, new genres, and music from different cultures that I would never have been able to listen to before. Where is the commercial service that offers anything close to this?
Spotify's library isn't even close to what WCD's was and is missing some copies of tracks/albums and/or just has the wrong versions flat out.
And the efforts of hundreds of thousands of engaged music fans who deleted bad tags, promoted good ones, made the connections.
Furthermore, Spotify hardly provides any tools to promote and showcase a high quality, carefully compiled playlist. I can share a link, sure, but that's the most basic of paths to new potential listeners.