Let's take it one step further. Unless one is proficient in using a gun and is accurate, the weapon is still virtually useless. Even if one has hours of training and hours at a range, the body chemistry changes once something like an intruder enters the picture.
Add the addition of adrenalin to the scenario which will probably make you fumble with locks, ammunition and so forth, you're more likely to become a victim rather than a hero.
Most people would be better off stocking their pantry with cans to throw at an intruder than buying a gun.