Roon offers much more than just Tidal.
It offers a forum full of advice from snarky, defensive, rude and often hostile Roon fanboys.
It offers the ability to search your music collection for things you know are there but which Roon can't find.
It offers a development team who are actively opposed to introducing features that its customers frequently and repeatedly say they want.
It offers helpful information about the music you are listening to - such as who the Beatles are, or what Jazz is.
It offers an inability to search for classical music in any useful way.
On the plus side, it does look nice.