There’s a subscription fee to use the app they developed, Plexamp. It offers features that their other apps don’t. However, access to your Plex server is free. Those users can use the free Plex app or the web interface. If they don’t want to pay the subscription, they can stick with Spotify. If your library is so limited, maybe it’s better they do? Or, maybe they could also access other Plex servers which have a less limited selection?
There’s a subscription fee to use the app they developed, Plexamp. It offers features that their other apps don’t. However, access to your Plex server is free. Those users can use the free Plex app or the web interface. If they don’t want to pay the subscription, they can stick with Spotify. If your library is so limited, maybe it’s better they do? Or, maybe they could also access other Plex servers which have a less limited selection?