One interesting use of this I think is for people who are paranoid about Google Home recording them (and there's a lot of those on HN as showcased by the Echo Look thread). You get to make your own device, where you have full control of how audio is recorded and sent to Google, so you can be confident that nothing is being sent over without you knowing.
Will this allow some inspection of what exactly is sent? Assuming it's the same Google Assistant installed on Android it'd be possible to then know for certain the level of spying.
Like I said, I'm fairly sure the sending is all done by you. It's an API that receives audio data, and sends back text + audio data. You're in full control of what happens on your end.
I was trying to find more info about their Term of Service for this, would I be allowed to build an Alexa/Google hybrid device? Would it be ok to sell the same device but with either option available? What other gotchas are there?
Interesting... Maybe this is the way to bring Assistant to the desktop? (and, perhaps, to Linux?)