It is serious stuff, which is why you don't use birdshot. If you HAVE to pull the trigger you've gone beyond the 'maybe' line. Birdshot has been shown time and time and time again to not penetrate tissue alone well enough to be considered reliable much less any variables like clothing/distance/etc. In the perfect situation, well you wouldn't be in that situation to start, but in the perfect situation it MAY work. But you have to plan on the worst possible person being the reason you have to pull the trigger.
The worst possible person isn't going to stop because you pointed a gun at them. They're not going to stop because you ran an action. They're not going to stop if they get surface damage. They're not going to stop if the receive an 'eventually' fatal wound. They're only going to stop if you stop them. If that's the case and what you're using CAN'T stop them, all you're holding is the club they're going to take your life with (or the wifes, or the kids...)
Or if the round you choose to use is effective at 5 feet, and what they're using is effective at 25 you've just given an accessory arm to the person that killed you from down the hall while you were busy making noise and muzzle flash. You don't bring a knife to a gunfight or a slingshot to a snipers nest.
I know where my kids are, I know where they sleep. It's 1% of the house that's a no-shoot zone. I would prepare for the 99%. Likewise I know what buckshot will do and that to hurt a neighbor in the unlikely event they ended up in line of a stray pellet the buckshot will have to do what buckshot won't do.
I know that in a typical home at typical ranges you would encounter a badguy presents more of a target filling area than a non-target area in a hallway, door etc. If you're the type of person who hears a noise and empties a mag into a room, well I again say you need a poo-stick instead of a pistol. IMO I can't think of anything I own that I would kill someone for so I'm not concerned with shooting standing in my living room while I'm standing down the hall in my bedroom and hoping that I hit and don't pass through to the neighbors.
LEGALLY in Wyoming, once you enter my house illegally, I own you. And I can defend my property as I see fit, the old castle doctrine. Not as extreme as other states fortunately. But regardless of my legal standing, I can buy a new TV after I run you off. If you choose to stand and fight instead, well I like to fight, I'm better trained than you, I'm faster than you, I'm stronger than you and I'm better equipped than you so good luck
And if somehow you make it through me, you have to deal with the wife who has been shooting longer than I have. And she'll be ANGRY.
^this does read like I'm coming off as a hard-[beeep] and it's not intended to be that way, just hard to put in writing what I can do in words better.