I just got Roon ARC working (manual config of gateway) and I find it useful in two unexpected ways:
1- No need to have an iTunes library in my phone…
I used to maintain a lossy copy of my music library in iTunes and sync it to my phone (which is why I have a 1TB iphone), mostly because I enjoy lots of odd music or specific releases I don’t find in streaming services. With ARC I don’t need to do this anymore - it is true I would not have them in my phone but would have to stream but these days this is not a major drawback for me.
2- Have my music catalog with me all the time
I struggled with this one: Looking for music away from home (new/used record store, web) and trying to recall: Do I have this version on CD/download? Do I have the vinyl record? No more. I can see if I have it ripped, and I have started tagging all albums I have in digital form with a “Vinyl” tag to know I also have the record version.