A ceremony is a machine that uses emotions to change people.

This is a great little phrase. And, in the church, I think ceremony is a useful or harmful machine in the ways you mention. And I think the potential for emotion-alteration is greater in a ceremony than just regular life. Not only at weddings, but in all kinds of formalized ceremonies -- funerals, baptisms, worship services, etc.

Generally, it seems to me that adherents of religion enjoy the experience. It is meaningful and sometimes even euphoric. And it "gives them the emotions they want to have." It's a win for them in every sense...apart from having to accept nonsense. But they don't seem bother with that aspect from my experience. (In that way, it all functions like an anti-fatalist mechanism for the believer...)