Except that the device (service) is not streaming / transmitting your audio except when you indicate to it - in exactly the same way as you would with "Hey Siri

Except that the device (service) is not streaming / transmitting your audio except when you indicate to it - in exactly the same way as you would with "Hey Siri" or "Ok Google" - that you intend it to do so. (Or if it makes a mistake and falsely detects the wake word; again, something that your mobile phone is also capable of doing.)