Spotify's aim is not to help us discover or appreciate music so much as to make us dependent on the platform itself, and what it can specifically do — allow us to use music as audio wallpaper for continually decorating our lives. Thus it must convince us that we need access to all music (and thereby nullify the possibility of our choice of music signifying anything about ourselves) in order to have any music we might need — not to show who we are, but to purportedly enhance how we feel — ready at hand.
Despite its vestigial sharing infrastructure, Spotify's implicit promise is that it offers a safe forum in which you can reveal your tastes to yourself rather than be compelled to express them. It allows you to consume your identity rather than perform it, much as all the other automated recommendation systems do. The underlying idea is that our taste is not especially dynamic — once the algorithms peg you, they can continue to make us content by feeding us more of the same. At the same time, we don't need to express ourselves to others to have our sense of self reflected back to us; the app can stand in for that social interaction. It lets us experiment with ourselves without apparent social consequences. But the consequence may be a reduced tolerance for social risk.