Google Nest Community

have a bedroom display for my Google home products and security. I don't say anything, or the phrase "ok Google" I could say my dogs name or be on the phone ( and was with Google support) It said " it didn't know, but this is what it found on the web...

If ultrasound sensing is to help,make things easier. Why do you include speakers for help via the screen display you mentioned in the information. Why we didn't sound? What is the purpose to know that somebody went near a speaker? That's not logical ...