This pisses me off every time I see it. It makes Spotify look great and that's why they share it. It completely ignores the fact that they offer a free plan that a large percentage of their users enjoy.
The important figure in my mind is the per stream rate and when I last checked Apple was paying double the rate Spotify does (because Spotify's per stream rate is dragged down due to its free users).
Artists don't have a way to say to Spotify, only show my music to premium users and pay me a higher rate. It's one (of many) ways in which Spotify takes advantage of artists for its own gain. Another being their new policy to not pay artists who get less than 1000 streams on a track in a 12 month period. They just blanket decided they were going to keep that money for themselves.