One of the scenarios enabled by today's smart speakers is the ability to control music playback across all the devices in your house so that you can listen to your favorite tunes as you move around. Up until now, Google's ecosystem only allowed this to be done using its Home speakers and Chromecast Audio devices, leaving the video-capable Chromecast out.
That changes today, as Google is now enabling these devices to be added to speaker groups so that they can serve as speakers for your music playback alongside Google Home devices. Given that the audio-only version of Chromecast could already do this, there doesn't seem to be a reason why the more capable adapter wouldn't, so this is a welcome change.
Smart displays, such as Google's own Home Hub, are also set to receive a similar update in the near future, adding even more devices to the list of speakers you can use for multi-room setups. It's still unclear when this will happen, however.