You might feel weird asking others for money. Nowadays, some couples wait till they’re older to marry. They have worked and saved, and can take care of themselves. They’re not 19 with no savings and no plates.
In my experience, couples aren’t making that much money off the Money Dance (also called Dollar Dance). Realistically, it’s just a fun time to connect with each guest. You might have an aunt who’s slightly timid; she may want to talk with you, but not want to fight off the hoards of others preening for your attention. The Money Dance is a great time for her to connect with you one-on-one. That can mean a lot to some family members. When announcing this dance, I always focus on the connection aspect. “Come share a quick moment with the Bride and Groom”. Then it feels less tacky, and more about the connections and relationships.