No idea how long this has been available but I don't go into the app much, isn't that the point with a voice system?!?
But, whereas I used to always have to say "on the kitchen Sonos" whenever I asked the echo in the kitchen for music, now I don't and it default plays on the sonos now rather than the echo.
It's the small things that make life better.
In case this saves someone else 4 words many times a day. Or having to repeatedly cancel music on the echo and restart on the sonos.