Given the distances inside your home, and maximum distance of 80 yards, what do you perceive the benefits are to an AR15 over a pistol caliber carbine, or just a pistol?
Even a suppressed AR15 in 5.56 will be extremely loud inside your hallway or house versus a suppressed sub-sonic pistol caliber.
Yes the 5.56 does more damage and yes the 5.56 does not over penetrate through interior walls as much as pistol calibers, but depending on your home's layout, construction, and your home safety plan, a pistol caliber may be the ticket.