Roon is fantastic for combining streaming services + local downloads into one seamless music app. Doesn't work with Spotify or Apple because they don't let you tweak the meta tags.
It's pretty perfect for me because it fits all the things I wanted in a music app:
*I have a TON of downloaded music in all sorts of file formats (WAV, AIFF, MP3, etc.) and I also have a Qobuz subscription for high-res audio. They all show up in one app/library and it automatically selects the best quality if I have it downloaded + favorited on streaming. You can also manually set a preference to which file you want to play. Sometimes I have a specific CD mastering I like that's lower quality than Qobuz but sounds better to me...
*Lets me do multi-room audio. We have lots of random speakers around our house in different rooms. I can use the Roon app to play music in my living room on my streamer, or in my office on my turntable/amp/DAC setup, or in our breakfast room on Sonos. All controlled from one app that has my downloads + Qobuz.
*The software UI is just fantastic. I used to have to use the Lightning OS that came with my Aries Mini and it made me not want to stream music. It was annoying to select albums or choose between Qobuz/downloads.
There's lots of other features too that are great. I found myself using the app every single day (I work from home now) so it was worth just going in on the lifetime sub when I did.
As
@Joe Mac said, it's probably overkill for most people. But if you have a ton of downloads and stream music a lot on Qobuz or Tidal, then it might be worth looking into. I ended up building a little NUC to house all my downloaded music on and installed the Roon server on it so can even listen to the music on my server on the go at home.