A key rule of self defense:
NEVER, EVER, NEVER count on getting more then ONE shot.
Bad things happen. The gun jams, the ammo misfires, the bad guy gets off a lucky shot, a meteor comes through the roof and knocks the gun from your hand, etc.
You'll be lucky to get off one good shot, and since you cannot be certain of getting even that one, you BETTER make it an effective one.
Legally, if it's serious enough to fire a gun at someone, it doesn't matter if it's a cotton ball, or an armor piercing round from an elephant gun.
If legally it's serious enough to shoot someone, it legally doesn't matter if they live or die.
If it's NOT that serious, shooting a cotton ball is WRONG.
To quote famous Border Patrolman Bill Jordan:
"Like being slightly pregnant, there's no such thing as shooting someone "just a little bit. If you HAVE to shoot someone, shoot them GOOD".
"Less lethal" ammo is ONLY for use by the police when they are backed up by lethal ammo, and the situation is such that they think they can take a chance.
For a home owner to use it is suicidal.
Imagine this situation:
It's 3:00am in your front room.
You confront an armed intruder, you "give him a break" by shooting a less lethal round.
It fails to stop him, and for some reason you aren't able to fire another shot, lethal or not.
You're now facing a armed intruder who sure isn't going to be happy, and who ISN'T going to be giving you and your family "a break".
Only a fool counts on getting multiple shots in a real encounter.