I think in all likelihood, decibel noise won't be that big an issue given how "amped up" you be. What's your preference in a HD situation, confront the threat, or have them leave without harming anyone? That would dictate your actions. If I was intent on killing the intruder, sure suppress your firearm, and keep the lights off. BUT if I'm in a home where loved ones are present, I want to be as loud as I can (with the firearm), and as visible (turning on lights), to encourage the intruders to reconsider pressing forwards and to alert neighbors or passerby.
If someone's in my house all bets are off. I don't owe them anything. I want every advantage I can get. I'm not giving anyone the benefit of the doubt at that point. They are in my house, my castle.
Kut, I don't want to derail this thread again but your line of thought baffles me. Please elaborate. PM, New thread, whatever... I can't wrap my mind around what you're conveying here.