Supposedly it is
Android
Google has made things a little confusing here, as you can use the casting protocol to mirror your phone. First, make sure your devices are on the same Wi-Fi network then open the Google Home app, find a device that supports mirroring, such as a TV, then tap to open. Next, select Cast my screen followed by Cast screen then Start now.
To disconnect, return to the device menu in Google Home and tap Stop mirroring.