If there was an upside, generally speaking, it would never have had to have been forced by law.
That said, women still pursue marriage, generally speaking, because they believe in men. They believe men have the capacity to be companions and partners. And they want that.
Also, that's what men are offering when they pop the question.
Women are learning, through years of bitter and hard lessons, that it's a false promise or men don't really want to deliver. In many cases, that the guy who made that promise, really kind of low key hates you. They're learning how common it is for many men to marry to get served and little else.
Marriage rates are falling. Divorce rates are rising.
Because you're right. There's no sense in tying yourself to someone who can't truly love and only wants to use you. You shouldn't have to wait 30 years to be acknowledged.