I think it's a valid defence actually.
It's not just the threat of violence - that's covered by standard coercion.
It's not just self-interest re the economics of the family.
It's the long term threat to the relationship, that women (or men) are responding to in this situation.
He loses his job, family is much worse off because of it and she could have saved them it, he's got a stick to beat her with for the rest of their marriage. Life has a momentum of its own, you don't know what is going to happen as a result of the points/ ban and you don't know if that decision is still going to be causing trouble in your relationship five, ten, twenty years down the line. You also don't know, if it might be a contributory factor, to your relationship breaking down altogether.
Given that the state and society are constantly telling women that they are the guardians of relationships and that they should be working hard all the time to keep the relationship healthy, happy, etc., it is right and proper that the law recognises this cultural assumption as a potential form of coercion.