As someone who just had his husband in the hospital for a month. That shit does matter. (We also filed healthcare proxies just in case...) But let me tell you. I've done Domestic Partnership, Which was cute. I even thought about just going to a more legally recognizable LLC before we wed in 2013. ( would be better if we got hurt south of D.C. than a marriage cert)
Wills and estates are fine. But without even a marriage certificate, my husband's ex wife would have entitlement to parts of our collected stuff. I always felt I shouldn't have to hire lawyers and pay for all these documents just because we both have a Y Chromosome. Granted we have to do the wills and estate stuff for the little we do have since I have a religious sometimes vindictive family should something happen to me I could see them trying to kick him our of our house and give my stuff to a church.
The ability to make decisions for children are easier for married couples, simply based on adopted kids where the birth mother/parents are still around. That's how I read it. Thankfully I have my dog. Way better than children.
While I agree that marriage isn't working, to have them give us something else that is not entirely equal would set off balances one way or the other. I never did intend to get married, we were together for almost 12 years when we did. Why? Work's insurance wouldn't cover a domestic partner in a state that allowed marriage. (I get their point, if we require straight people to be married to put them on insurance, why not make it equal) so I planned, invited, and had my wedding in 4 days.