Having lived through my parents' unhappy marriage, I'm strongly resistant to getting married.
However, my current partner has better retirement benefits than I do (both Social Security and pension benefits). I recently joked with him that we should marry so that I inherit his benefits should he kick off before I do. That would be an unpleasant reason to get married.
Regarding health insurance, currently it looks like we're better off not being married. That's probably also true for tax purposes.
Getting married for taxes/insurance/power-of-attorney/etc is at least a tangible benefit that can be shared and appreciated between two people. So many people get married simply because they used to like each other, are afraid of any change, and buckle to overwhelming social pressure.
However, my current partner has better retirement benefits than I do (both Social Security and pension benefits). I recently joked with him that we should marry so that I inherit his benefits should he kick off before I do. That would be an unpleasant reason to get married.
Regarding health insurance, currently it looks like we're better off not being married. That's probably also true for tax purposes.