I guess nowadays a wedding is a ceremony mostly important for the woman... but originally the purpose of a public wedding ceremony with lots of guests was to essentially socially cement the relationship in such a way that it will be hard for the wedded couple to separate without social consequences/ostracism. And the point of that is I guess utilitarian, which is to protect the family structure for the sake of children. But I guess nowadays people don't understand or don't care that the purpose of marriage are children, not having a fun party.