Robert, let me illustrate by reiterating a few stories I have told before. (And contra @Sallah_48, it is not about the obsessive virtual music collector. In fact, I strongly disavow that: I do not want to be a librarian or curator, I do not spend time polishing my metadata.)
It is not about the metadata but about what the metadata allows you to do, and what it allows you to do easily, casually, following whims.
In 2011, I read that Paul Motian had died. Motian was a bad-ass, he broke new ground. I looked at my albums with him. But of course, being a drummer, most of Motian’s albums are not published under his name, even though being a celebrated drummer and bandleader and composer, some where. But in Roon (yes, in 2011 I had Sooloos, Roon’s precursor), when I looked at Motian, I could see all the seminal albums that he played on in the 50s and 60s, like Bill Evans’s Waltz for Debby. But I also had Live at Birdland with Lee Konitz, an album that was released a few months before Motian’s death – ooh, this one also has Brad Mehldau, didn’t use to be fond of him but this is great stuff, let’s see what else Mehldau has done. And Motian had played with the Italians like Enrico Pieranunzi, and with Scandinavians like Bobo Stenson, and on and on. Most interestingly, he had very recently played with young musicians I love, like Anat Fort and Samuel Blaser. But looking at the library, I noticed very few recordings with Keith Jarrett, which is odd because I have lots of Jarrett. Click, looking at Keith Jarrett – of course, now I remember that they played a bit together in the early days but didn’t get along, and Jarrett mostly played with Jack DeJohnette, in fact I recently heard them play in Seattle. Click on DeJohnette – the same profile, he played on seminal albums in the old days but also recently with Esperanza Spalding and Rudresh Mahantappa (and Sting). And look what Mahantappa did…
Of course, this exploration took the entire weekend, listening to all kinds of great music. And with Roon today, it would involve discovering and playing stuff I didn’t have on Tidal.
The point is, very few of these albums would be discoverable on a conventional system because they would be listed under Bill Evans or Keith Jarrett or Enrico Rava or…
Any system can play an album when you know what you want – your phone or car can do that. But if you are going to explore and enjoy the music in a richer way, as above, this requires that you have the database of relationships in your head. And unless you are a combination of Einstein, Gallup and Webster, you miss a lot.
And this kind of exploration does not involve any kind of sophisticated metadata traversal, it’s just clicks on names.
The Motian story was about a jazz classic, but I did a similar exploration of Hélène Grimaud after the cadenza kerfuffle that lead to the break with longstanding collaborator Claudio Abbado. And the April, 2017 album of Bach Trios with Yo-yo Ma and Chris Thile and Edgar Meyer – Thile is a MacArthur award recipient who has played folk and bluegrass music, also did an album with Brad Mehldau and took over NPR’s Prairie Home Companion after Garrison Keillor (yes, even this info is in Roon!).
The stories go on and on. This is what I call “serendipitous discovery”. It adds immeasurably to the enjoyment of the library, both my own and the world’s.
I hope i have made it clear that Roon does not compare with iTunes or JRiver. Lots of systems can play music, but not help with discovery.
(In fact, the difficulty of exploring is probably the reason people rely on Spotify’s public playlists – “I can’t discover music so I will rely on others to tell me what to listen to”. That’s not me.)