If the average gun owner is asked what the most important weapon to own for home defense is, the answer often is the 12-gauge shotgun. Yes, some will say go with a pistol and others will prefer a semi-automatic rifle, but the 12 gauge is probably the most commonly recommended firearm for home defense.
There' good reason for that. Twelve gauge 00 buckshot or any other kind of defensive load is devastating at close range and will incapacitate the attacker, likely with only a single shot. The pump-action shotgun itself is a very rugged, reliable and simple weapon that practically anybody can pick up and quickly learn how to use.
Many will claim that the pump-action design is now outdated in the age of automatic rifles such as the AR-15 or AK-47, and indeed, there are some very high-quality semi-automatic shotguns out there. That said, semi-auto shotguns (at least the quality ones) almost always tend to be more expensive than pump actions, and they also can be just a little more finicky with certain types of ammo. For those reasons, the pump action is still an excellent defensive weapon even in the 21st century and likely will continue to be for many years to come.