I got my headphone, and overall, I am quite happy with them. The Swap feature with ARC is quite cool I must say. But, what would make these headphones feel like I bought a high-end SONOS product is for me to be able to use the SONOS grouping, which I understand is not a feature.
But...if now we can swap the HDMI input from ARC to the headphones, I do not see why I cannot use my ARC or ERA300 to drive the headphones through sonos app without a TV. Let us swap from supported speakers for them to drive the headphones, and we have a good-enough product for now that feels and works much more integrated with the SONOS system.