Google announced at I/O that Home was going to learn a few new tricks, including good old-fashioned Bluetooth streaming. Even though Bluetooth is as old as the hills in tech years, it still took some time to get this feature ready. It's rolling out now, and you might already have it on your Google Home.
Google Home has always supported streaming audio, but that was as a Chromecast target. Your app needs to have Chromecast support baked in. Casting also requires an internet connection for most apps because the target is just reaching out to grab the feed. Google Home will work just like any other Bluetooth audio device; when connected, all media audio will be routed through the speaker in Home.
This feature is rolling out silently to devices. A few AP staffers have checked the Home app to find "Paired Bluetooth devices" listed under device settings. Take a peek and you may already be able to stream over Bluetooth.