Honestly that would be an improvement. My first “that’s strange” moment with Roon (where I learned more about the philosophy) was searching for songs on TIDAL and being unable to find them. Roon’s advanced music exploration is amazing – related artists! composers! engineers! producers! session players! So I’m puzzled why it gets the basics so wrong. My example: search for “Nina Simone” and you won’t find “Feeling Good” or vice versa. As a music lover, I find that a bit depressing.
There is a plot twist though! Because of the “composed by” and composition search, I found wonderful renditions that I never knew existed. Even better is that I can find more songs written by Anthony Newley and Leslie Bricusse… and anyone either of them collaborated with… and so on. It’s a delightfully endless habit hole 
What would it be like without TIDAL integration? I honestly have no idea since I haven’t used Roon without TIDAL. Does Roon tell non-TIDAL users that there are 84 renditions of “Feeling Good” out there? I’m guessing not…
Here’s one thing I don’t understand: how does Roon have the information for CDs? The original purpose of this thread is to show how valuable Roon is even if you don’t use TIDAL. So, does Roon show you who played bass on your CD albums? If so, how does it get that information? Assuming it’s not embedded directly in the file metadata (pretty sure it’s not), then might the same source of information be applicable to other streaming services?
Agreed, Spotify is a lot better with recommendations in my experience.
So… while reading this thread, I had a bit of an epiphany about Roon and cloud services.
Roon is great at telling me how music connects to other music. Cloud services are great at telling me how music connects to society.
In other words, Roon can tell me that “Feeling Good” is a song composed by Anthony Newley and Leslie Bricusse, with 84 versions on TIDAL. It can tell me that John Coltrane recorded a version of it, and that Donald Corrado played French Horn on that album, and that Corrado has played horn on a dozen other jazz records. That’s certainly not something that TIDAL can do (although I suspect that some form of discovery aided by allmusic information could make something like that possible).
What Roon can’t do, today, that cloud music services can, is know that if I tell you “Hey check out the song Feeling Good” then I probably mean the recording by Nina Simone, or maybe Michael Bublé.
Which, for anyone coming to Roon from a streaming service, causes a WTF moment. Of course searching a catalog of music is going to show us what’s most popular! That’s how every service works! Why wouldn’t Roon do the same? Well… because it began life in a completely different way. It knows all about how music relates to other music, it just never knew anything about how people relate to music. That has potential to change with TIDAL integration. It just depends how far Roon wants to take it.
This does make me wonder if the discovery functionality that I personally love about Roon can be got by integrating with the Rovi API (which I suspect is the data source that Roon uses). I think an interface that integrated Rovi data with other cloud music providers would be amazing. I also suspect it’s easier said than done