Its a nice idea but as I found out with my Xbox Sonos app, turning the TV on will cause Autoplay to kick in on the Sonos HT device, and stop the music that was playing, so you either have to disable Autoplay or start the music after you have turned the TV on.

There is a third party Sonos app on the ATV right now, which looks very pretty but has never once worked for me. YMMV.

Are you looking to control Sonos or just display what’s currently playing?  If this just for display, then instead of Sonos creating apps for AppleTV and having everyone who doesn’t care about AppleTV complain about Apple favortism, why not have the device connected to the TV do the display?

If you have noticed, Arc, Beam and Amp connect to the TV via the HDMI ARC/eARC input on your TV.  If you switch the TV to that input, you’ll see a Sonos screensaver.  It would be nice if it simply displayed what’s currently playing instead.

You summarize this very well - thanks! Display is my main priority, but I really like the streaming function and control of my various Sonos speakers through the app. My Arc is connected to my smart TV (which also does not have a Sonos app), and my Apple TV is connected to the smart TV via eArc as you describe. So I can stream non-Sonos music to the Apple TV (which then sends the sound to the Arc) but it is adding hardware and software complications, and I can’t use the Sonos app to stream since I can’t choose the Apple TV for output.

And then when I start watching TV I have to jump through hoops to get the sound working properly again using the Sonos app. The easiest solution would be your Sonos screensaver idea, displaying what is currently playing.