Why do I need Roon?

It’s a free trial. See if you like it. Me? I love the integration of Roon with Tidal and I’m interested to see how Qobuz compares. Rich metadata, bios, lyrics, DSP if you want it, and cool “radio” function to create playlists. $10 a month or $500 lifetime? I’ve easily wasted that in ill-advised music purchases. The integration with Tidal is excellent. 

We do the yearly
i find value

I have been using Plex for several years.   It also now has Tidal integration and 30 day free trial.

I used to use amarra, pure music, and lastly audirvana. Roon surpasses them all for functionality and SQ. DS Lightning from Auralic and the LUMIN software would come in 2 and 3 behind Roon.
Roon provides such features that would, behard 

Roon provides features that would be hard for other vendors to implement for a free app. If you pay for an app specifically rather than a part of a product, you have the luxury of hiring more software developers that can tackle more features.