No it isn't. No one breaks into a house at night just to steal things. Most robberies are during the day for a reason. People only break into homes at night if they want to do something horrible to the people who live there.

Moreover, you don't have time for warning shots. If someone enters the room you're in, it takes less time to fire a warning shot and to gauge the response than it does for them to quickly run across the room and be on you.

There is only time to pull out a gun and fire several shots in quick succession. This is what people are trained to do in self-defense classes. Because anything else ignores how human beings and bodies actually move through space.