First, just having a gun protects yourself - criminals love soft, unarmed, defenseless targets. Just having a gun makes criminals move on to a safer target - dogs accomplish this on a lesser level. Second, you may need to dispatch a dangerous animal where a stick won't do the job. Owning a gun carries a LOT of responsibilities with it though: You must be safe with it, be good with it and never brandish it unless you intend to use it if necessary.