It doesn't seem possible to delete a playlist or remove tracks from one :( Other than that it's pretty great, maybe I can automate my playlist management now :)
Same conclusion we also had in https://github.com/mopidy/pyspotify/issues/139 when looking at if we should move away from libspotify in favor of the new web API. For now I would stick with libspotify wrappers until a more complete version of the API comes out.