If you have one of Facebook’s Portal Devices, you can assume that the words you thought were private when talking with your family were not private at all. In fact, your words may have been transcribed and are now saved for whatever use and whatever purpose Facebook wishes. Given the company’s past actions, we can assume the desire is to invade your privacy in some manner is planned so that Facebook can profit from your words.
Mike Isaac and Farhad Manjoo have published an article in the New York Times that describes Facebook’s latest privacy invasion without your knowledge. See https://www.nytimes.com/2018/11/08/technology/personaltech/facebook-portal-review.html.