In addition to the stuff already mentioned about tax benefits and legal protections in case things go sideways...

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My family and my spouse's family are big on weddings. If folks are invited, they'll come in from wherever they're at across the world. I got married when I still pretty young, and at the time the wedding cost about the equivalent of four months of our combined salaries. It wasn't an elaborate wedding but we spent a lot of money on really good food, and a really good photographer (everything else we did pretty cheaply). I regretted spending that much money for a really long time and wished we had put the money towards buying a house sooner. My perspective changed when our family started to die. Turns out our wedding was the last time a lot of our family saw each other. My wedding was the last time my sister saw my grandparents. The last time my spouse's brother saw their grandfather. I told the photographer to spend as much time as possible photographing the guests and guess what, those photographs were some of the last professional pictures taken of a lot of our family. Ten years after our wedding, during what turned out to be our last visit with my spouse's grandmother, she told us how our wedding was the best she had ever been to and how much she enjoyed it. For so long after our wedding I cringed thinking about the cost but now I wouldn't take it back if I could.