@greenman @pjf Nice. Actually, my main use of the function is confined to the same room. I have a touchscreen "player" without any audio output sync'd to the main device in the room so that my whole family has a more accessible control interface, and no-one has to have an app installed on their phone to control it.
If anyone DOES use an app, the touchscreen defaults to the "now playing" screen, with album art etc, so it's not totally pointless.