What does Roon do?

spotify has a great interface software and music selection and search but through a serious 2 channel hifi system the sound of tidal and quboz is immediately noticeably better... less hash, cleaner transients, more calm and ease

as for roon, i have many friends serious music lovers who swear by it - i have spent many thousands on my system but i must admit i cannot get over paying them 10 bucks a month ongoing for an interface/organizing software... then pay for streaming service on top of that...ugh

I too am trying to figure out what Roon is or does.  I activated it on my Innuos music server on Sunday and started the free trial.  I was using iPeng to manage the server and play Tidal.  I am not using the Roon DSP.
With Roon music from either the server or Tidal is more euphonic and harmonious.  I need to go back thru the set up to see if I have the MQA set to on.  Maybe I am getting some unknown DSP.  My DAC does not support MQA.  It is different and so far I like it.
Before Roon I was streaming Tidal from a Wyred 4 Sound upgraded Sonos Connect's digital COAX to my DAC or thru the Innuos's Tidal integration.  Tidal always sounded good but easily never as good as music from the music server  Now Tidal sounds amazing and I mean amazing.
For me it is an incredible value given the costs of hardware and music files.  I won't be purchasing digital files to listen to.  Tidal's library is huge.  I am going to try Qobuz soon.

The advantages of Roon scale with the size of your stored music.  With 10,000+ ripped CDs, SACDs, hi-res downloads, and vinyl-to-DSD conversions, I wouldn't contemplate any other approach.  If you're only streaming it probably doesn't make sense.