Another thing i found is that green dot does not indicate that microphone is being used. If microphone permission is enabled in system settings, google assistant will have a constant access to microphone, without showing green dot. And even if on pixel microphone permission can be disabled, on most other phones, there is no a system setting to do that. I dont know if its just a toggle which was removed, or a feature entirely, but it does no tchange the fact that on that phones, microphone is accessed at all time.