Single button press to output anything connected to your Sonos system to the Ace sounds really nice to me.
I have my Series S, Switch, PC, Apple TV, etc.. all outputting to my Arc setup. Would be really nice to just turn on my headphones and have everything automatically output to those instead.
That is what made me interested in the Ace to begin with. I saw someone posting about how the Apple TV can be used as a receiver for consoles. I don't think it would work seamlessly with my Sonos 5.1 setup, which is a point in favor of the Ace. But my headphone use cases are already covered except for one edge case that is just inconvenient, not impossible.
Apple TV - bluetooth headphones for all streaming
PS5 - wired headphones
Switch handheld - wired headphones
Switch docked - repair bluetooth headphones
I might end up with an Ace at some point, but $450 seems like a lot to ask for the single button functionality.