It would be cool if we could record all the DJ actions but not the song(s) themselves. Then recall them when needed. One use would be: Spotify will not allow recording of copyrighted material. This is understandable. However if I could record my live actions then recall them when this song is loaded I can recreate the experience without any violation of copyright. Later if I do not have Spotify I will not be able to play that song.
This idea has ramifications beyond Spotify, I may just want to record and recreate a performance without actually taking up disk space recording another version of the song.