I'll reply with a question: What's the point of having a gun if you won't use the gun? Plenty of people won't.
And yet another: What's the point of having a Mossberg when you're not home?
Criminals tend to avoid wired properties. It's a fact. If someone is actually intent on "picking" a target, kicking in the door, you can probably bet they are there for you or your property specifically, and you may not have time to get to your gun. Where does your Mossberg sit, leaning against your bed where you sleep? Under your pillow?
An alarm, like a gun, is merely a "tool" in the risk management of home protection, along with trimmed shrubbery, proper lighting, fences, etc. Personally, I'd take all the foregoing, the alarm system and a gun.