What is a supplementary credit card used for?

Supplementary cards are like extensions of the main credit card and are mainly used to share the principal cardholder’s credit benefits with their loved ones. These individuals might not be eligible for their own credit cards because they are too young, have a poor credit history, or don’t have a steady income. With supplementary cards, they can enjoy the convenience and advantages of using a credit card, benefiting from the creditworthiness of the main cardholder.