I'll admit that the technical benefits are not necessarily audible. Their RAAT protocol is supposed to eliminate any jitter or timing issues with digital transports. It does offer wide hardware support though and great features.
- You can stream using your phone or PC or any Roon Ready device.
- You can simultaneously play different content in different zones or link zones together and play the same content on different zones, with no sync issues.
- You can transfer content from one zone to another on the fly.
- You can pass through content or resample to higher bit rates and apply various DSP functions like volume leveling and parametric EQ.
- It supports local files, a variety of streaming services and internet radio.
- End points can be anything that is Roon certified from a Raspberry Pi3 to PC/Mac or one of their own or 3rd party streamers if you don't want to setup things yourself. That includes Chromecast and Airplay enabled devices that don't have native Roon support. I can cast to my NVidia Shield and use Airplay for my AVR.
- End points with video can display album art, static lyrics or even karaoke lyircs if available and it's all configurable.
- Roon automatically plays the best version of a file. I have both FLAC and MP3 files. I play FLAC at home but maintain smaller MP3 files for my mobile and my car (which does not support FLAC). If Roon has both versions in its library, it will play the better quality file.
- They added the ARC phone app which lets you access your Roon library away from home.
- They have a large database of artist and album information that lets you explore other areas of music.
- Their genre matching is very good. You can choose one song or an album and then enable "Roon Radio" which will play similar material (like Apple's autoplay or match).
It's still my favorite interface with various search options. I can build playlists on the fly and if I don't like what Roon Radio wants to play, I can modify the playlist and it will adjust. The karaoke lyrics display in Chromecast as well if you configure a display but I wish that they had a native Roon client for the NVidia Shield, which does not support multi-channel audio via Chromecast. The Roon client for the Pi seems very stable. I added a DAC HAT to the Pi for analogue output and haven't touched it in months. It gets software updates from my Roon server on occasion but I have never had the need to reboot it.
It's expensive for a software solution though. I should have paid for the lifetime subscription when I first installed it.

I wouldn't pay that much to run it on one device, but for multiple devices in a home I think there is value there.