Don’t want to open a can of worms here, but for me Roon would be really complete if you could purchase music from within Roon itself.
My ideal would be once I’d discovered music I like (via say Tidal, or another service), I could select that album and say ‘buy’. Roon would then go away and get prices for me on CD, and downloads in various formats, and present the info in a nice GUI - including say any subscriptions I have already (maybe Qobuz Sublime where high-res downloads are often discounted).
On confirmation, if I’m not registered I can add payment info, and if I am it will just used saved data, and unless its on physical media, download the stuff and add it to my library.
I know this isn’t trivial, and is perhaps beyond what you’re trying to achieve with Roon, but to me it would be heaven.
Of course it could be disabled, so for those that don’t like such things in their music playback software, they’d never know.
Perhaps something for version 2 or 3 maybe? And you could always start with a smaller number of providers, i.e. Qobuz.