The new Nest Mini and Nest Wifi from Google have ultrasonic detection, so they can light up when you are around. Google is now implementing ultrasonic detection for its smart screens from Nest Hub and Nest Hub Max, allowing them to show you information depending on how close you are (through Android police).
Engadget have a early glance at the October position. Apparently, when the smart screens detect that you are in the area, they retrieve information such as timers, your commute or weather forecasts, and as you move a little further away, the device's user interface changes to show larger fonts that are easier to read remotely.
This feature can be especially useful for the smaller Nest Hub because it does not have a camera, so it can now use ultrasonic detection to display proactive notifications, such as the Nest Hub Max, according to Android police. However, these reports apparently still do not display any personal information because the ultrasonic detection cannot see who is looking at the device.