You don’t need a Google Home appliance to control a Chromecast with your voice: Thanks to a recent update to Google Assistant, you can do so from your Android phone now as well.
I use this feature with Google Home all the time, but the functional parity makes tons of sense. And it allows someone to access Google Home-type functionality in a room—or home—in which there is no Google Home.
It works as expected. Just press and hold the Home button on your Android handset, or say “OK Google” (or “Hey Google”) to invoke the Assistant. Then, just say what you want.
For example, to listen to The Beatles on the phone’s built-in speaker(s), you might say, “OK Google, play The Beatles.” But to play this music on a particular set of Chromecast Audio-connected speakers (or a group of speakers), you would add the name you gave to that in the Google Home app. For example, “OK Google, play The Beatles on the sunroom speakers.”
This works with video as well. If you have a Chromecast or Chromecast Ultra on your HDTV or 4K television, you can also direct content to those devices. For example, “OK Google, play YouTube on living room TV” would play recommended YouTube videos on that device. You can, of course, push music to a video device, too: “OK Google, play The Beatles on living room TV” works fine too.
From what I can tell, if a particular Chromecast command works with Google Home, it now works with Google Assistant on your phone too. Pretty cool.