My understanding is ROON does not do that and pulls music from all your digital sources seamlessly (?)
Yeah Roon would display your local library integrated with your online streaming service. I can't speak to that as my local file storage is attached to my Bryston Pi. When I want to listen to those files I switch the Bryston from a Roon endpoint to its internal player (MPD), only takes seconds to do. Someday I might get around to attaching the storage to the Sonic Transport that hosts the ROON server and indexing it there just to see what it it looks and sounds like. I think the Brysto/MPD combination sounds a bit more open and lively than ROON. ROON is fine for general listening. I think the only limit to the number of tracks in ROON is hardware. Lots of threads on it over on the ROON community site.