For me it is all about timing, I can remove a pistol from a holster next to my head and point it at the bedroom door faster than I can grab a scorpion that weighs several pounds from wherever it is stashed. But I can triple-tap and engage multiple targets way faster with my red dot equipped scorpion. Ammo capacity is actually the same, I have 16 rounds in both the handgun as well as the 20rd scorpion mag I keep on the nightstand. I figure with both guns and my wife we should have a handle on things (and there is a 3rd gun in case of malfunction).
If I hear something that is obviously a breakin, or sounds outside the bedroom door that do not sound typical, handgun. If I hear someone walking up the deck steps or what sound like someone trying to pry open a window, scorpion. The only 2 times I have ever grabbed a gun to take a look around, it had either been a wind gust or a stray cat that climbed up the deck steps, and my cats went nuts when they saw it.
Luckily, I live literally 2 minutes away from the county sheriff HQ, so a breakin is unlikely... however criminals can be stupid and not take things like that into account.