I'm not 100% sure but going to test it out when I get home tonight as I'm hoping it's going to solve an annoyance I have. Any time I'm home and use Google Assistant (on either Hub, Mini, etc) my phone also trigger's assistant (bc it hear's "Hey Google") but the action is completed by my smart home device (which I want it to do). But then on my phone I always get a notification that pops up that is simply the Google logo (and no other info). I was trying to find a way to not have this notification pop up every time I use assistant at home because I was constantly clearing that notification on my phone. I'm HOPING by turning off "hand-off" I will no longer receive notifications on my phone that the Action I triggered on Google Assistant was "handed-off" to another smart device. Hope that makes sense and hope that's what it's for! Will report later tonight