All jokes aside, this is more useful as "a button next to my bed that shuts off all the inside and outside lights, closes all the doors, activates the alarm, turns down the heat, makes sure the tv is off, and disables notifications until the morning."
I've also seen one used as "a button to hit on your way to work to shut off all the things you forgot to shut off."
A panic button next to your bed could be "turn on all the outside lights, save all the security camera footage somewhere extra, and tell me if any motion detectors outside this room go off any time in the next 10 minutes."
I imagine someone will want one that makes their cell phone make a noise, so they can find it.
Or, it's a simple way to add a second switch to a room (or hallway) with one inconveniently-placed switch.
For a young child who is afraid of the dark, a button to dim the lights to 20% after they're in bed, and automatically turn them off an hour later.
A wireless doorbell.
Etc.