I don't know how easy it is to implement, but I thought it might be at the "set an alarm" category.
Use case: For when you are already at bed and ready to sleep, but you realize you forgot to put the phone at "Do Not Disturb" mode, just sleepy-shouting it to the phone would be nice 🫠
And actually saying outloud to your phone "I will take a power nap. Do not let anyone Disturb me for the next 10 hours" surely makes the nap better. I am sure there could be other uses as well...