I'm not sure we would volunteer to be downrange with our cell phones . . .
First, Home Defense isn't about our last ditch effort to shoot it out inside the interior of our homes. It's about external physical security and what you do to keep them out in the first place.
Once inside, most ammo will penetrate the flimsy construction we call "stick built." Everyone worries about bullets penetrating walls, what will, what wont. The reality is people shooting at you thru your bedroom door, back windows, etc. Hollow core doors and triple pane E-glass doesn't even rate as well as two 1/2" sheet of rock. And if you are shooting back with the perps sheltering aside from the opening - better to have penetration and reach them.
Entirely the point of military ammo - to penetrate built up concealment and prove it wasn't cover. Again, a last ditch shootout inside the home? Think about hitting the target, even if they are behind a corner or furniture. Accepting ammo that won't penetrate or hit them means accepting a disadvantage - one they didn't. They could be be using ammo that does, and it's not what you want to put up with. You are trying to stop them as quickly as possible before they get a hit on you.
Moot point, you already failed to keep them out by focusing on the gun and ammo as your last line of effort, instead of exterior security. If anything the discussion on Home Defense is one based on complete failure to have a secure home in the first place. To do that, the first line of defense would be limited access to the neighborhood - a gated community with surrounding wall, which keeps out strays and limits thefts to your neighbors. Second, the same for that house, with exterior property alarms. Then a hardened exterior plus the discipline to make visitors cool their heels on the front porch - don't open the door until you know who they are. Most home intrusions are the homeowners fault - they open the door.
What ammo you choose to shoot at them is so far down the list of things to "fix" that it shouldn't even be getting discussion, but whatever, it's a gun forum and the shootout fantasy is something we replay over and over. Regardless - if you get into a shootout inside your home, you can only control at best 50% of the bullets flying around. Against multiple opponents, even less, and you can't pick their ammo. Your priority requirement is to get them to stop shooting at you and your family who is right behind you - as a backstop for their penetrating ammo?
Goes to a lack of appropriate education or training on the subject. I recommend a few months in Basic Training at the Infantry School, with at least two weeks in Urban Combat. Being able to shoot Opfor thru sheet rock is a blessing most third world countries don't offer.