A gun is more of a deterrent to me...Sort of like mutually assured destruction...Owning one and brandishing one means that someone needs to be willing to use it...Just cocking it will scare criminals away...And that first shot can always to into the wall...Circumstances allowing it of course...
Having said all that...Most people just own guns to collect them or shoot them at targets...
The problem with this type of weapon is that the bullet goes thru walls and other objects after going thru your intended target. It becomes dangerous to anyone in the line of fire... within several hundred yards at the very least. Not the best choice for home defense, this is mostly an offensive weapon.