What Jaxian had to say makes a lot of sense from the financial aspect, providing a sound reason for why the federal government and insurance companies would be opposed to the idea of polygamy.
On the other side of it, what consenting adults choose to do with their lives is their own business.
However, what is going to happen if the husband should accidentally die and all the wives and kids are left with the house? I would wonder about the legal implications in such a case and the problems that would present. What about remarriage, etc...