It also helps us keep our own behavior in check, so that we do not become abusers, and if we are already abusers, we can choose to change.
We are not talking here about sporadic domestic arguments, but bona-fide years-long, repeated, and delliberate abusive behavior. It's not something you become by accident. And it's rare that they genuinelly regret it (though VERY USUAL for them to beg forgiveness to manipulate their victim back into their clutches). In their heart of hearts, they mostly stay unrepentant.
I recall a TV documentary... they interviewed a work-group of 20 or so convicted domestic abusers. Only ONE of them actually admitted he had wronged his wife, and regretted it. The rest? They either denied it wholly (mind you, I'm not saying a wrongful conviction is impossible, but I doubt very much EVERY SINGLE ONE of those asshats was a victim of a miscarriage of justice), or claimed that "she deserved it".
I have the misfortune of knowing two domestic abusers first hand (one who physically abused his wife and children, the other who engaged onto psychological abuse -which yes, is a very real thing. Again we're not talking about misunderstandings or arguments here, but of years of gaslighting and manipulation to delliberatedly hurt someone-). They were both hypocritical, cowardly bastards who kept a nice, "stepford smiler" façade to the public. I don't think either of them was unaware of what they were doing.