I decided I cared less about this considering that I (and many others) already have a Google listening device with me more often than I'm in my kitchen: an Android phone.
Is there any evidence of Google actually doing this on a widespread basis? The Home is specifically designed to be an always-on microphone. My phone isn't.
I'm not sure if it's on by default, but the "OK Google" feature presumably requires an always-listening microphone on your phone.
The difference in the quality of the microphones make it quiet impractical in phone, but very easy in a google home device.