If you aren't religious, what is the point in marriage?

I can only speak to advantages in the U.S. Married people get a tax break; family health insurance is cheaper than having two individual policies; property pes easier to a surviving spouse, that is no will is needed for all property to go to the surviving spouse at the death of one - whereas if the couple were only living together the decease's property without a will would go to their parents or surviving siblings and the the surviving bf or gf would get nothing. There is an underlying sense of stability in marriage that simply living together cannot bring. That's all I can think of at the moment.