That's an interesting point.
I wasn't actually looking for family law connections when I read that case, I just thought that it was interesting.
I wish your argument worked, and it makes sense to me. I think though that while a spouse cannot make a financial decision on behalf of the other spouse, they can certainly make a financial decision for the marriage unit.
So if husband takes out $100,000 loan to buy a fast car, he can't put the loan in his wife's name, but the marriage unit now has a $100,000 loan that was placed there quite legitimately by the husband.
Either way, in the case I linked, I hope the winning family buys a fast car with their hundred grand and crashes it into a nearby pole. Such jerks.