Why I Let My 7 Year Old Buy Our Family’s Food

So when we went to the Burger King drive through a couple nights later to get family some quick dinner, he said “Mom, can I buy the food for you guys?”. Initially I said “What?!, No, I don’t want you using your money to buy our food, I buy the dinner”. But when he said “Mom, I really want to use my money so you don’t have to use yours” I just melted and said “OK, I’ll let you buy it if you really want to, thank you”.