A report on how same-sex marriage would be economically advantageous to New Hampshire, by the Institute for Gay & Lesbian Strategic Studies, finds that "savings from means-tested public benefit programs" would come to $400,000 annually. The report doesn't go into details, but it seems the explanation is that with marriage (as opposed to shacking up), household incomes are viewed by the state as combined, making it more difficult to qualify for public assistance benefits.
Part of the value of marriage is that it legalizes a relationship of mutual support, so those who might individually fall on hard times have a partner they can lean on. And that's a good thing. As long as couples actually do get married, which requires a hefty dose of internalized social expectation in addition to legal equality.
More: Readers provide context regarding the New
Hampshire marriage fight, in our posted comments.