It depends on situation and what you as an individual are most comfortable with. I agree, that a shotgun is not the best approach to clear a room with. However, if I was in a defensive position and had to defend myself and my family against an offensive attack, it would be with a shotgun, hands down. Taking into account nerves, darkness and the hostile situation, a handgun leaves too much room for error for me.
Secondly, the learning curve to effectively load, fire and chamber a round in my police 870 was about 1 hour with my wife and 2 boys. I have an 870 police with 5 round side saddle a youth stock installed. We practiced with reduce recoil OO buck and I feel pretty confident in their abilities to master the loading and firing sequence. My wife and 14 year old loaded and fired the reduced recoil multiple times without issues or complaints. I don't think she could even grip my Beretta 92, won't even go into loading and chambering a round.
While on travel I feel much better knowing the shotgun is next to her bed with 5 rounds in the saddle. Hell, I feel much better with it there when I'm home.