Setting up use of Apple Wallet for kids under 18

I would like to find a way for Apple to change this rule. It seems as though you were not able to attach a card to a wallet for a user registered under 18. However, this is very inconvenient with today’s world, having so many things using contactless payment. If an adult sets up and go to the motions to add a credit card to a child’s account, this would make life easier to be able to allow them to use money from your account. Apple Cash does not work for them to be able to use Apple Pay in stores. How can we change this?