A drone that knows how to go around the house and stream a video feed can be useful. For instance, you can check if you left your keys at home, or see if the stove was not left on, it can alert you if there is an intruder, etc.
A drone that can navigate the house (using the visuals it analyzes from the video cam, the map in its memory, etc.) Anytime you can remotely activate it and tell it to go somewhere in the house and show you what’s there. It can also be programmed to react to certain events, like sound, motion, external input (alarm system), etc., and alert you when the conditions you requested are met. You can also program it to do “the rounds” from time to time as an extra security measure, and alert you when something is out of order (like a change in the what it sees compared to last time. When not active it can land on its charging mat to recharge.