The plan for mopidy-spotify was to move towards web-api for everything we could to be on the official APIs where possible. So the end state would have been only streaming left on libspotify, then figure out how to get librespot and GStreamer to play well enough together (there is a plugin but it's missing at least one feature we need).
But as you can see in issue #110 this goal hasn't been reached yet.
But as you can see in issue #110 this goal hasn't been reached yet.