Final answer:
Having more credit cards or debit cards does not change the quantity of money in the economy, and it is checkable deposits that are considered money, not the debit card itself. Credit cards are considered short-term loans from credit card companies.
Step-by-step explanation:
In short, credit cards, debit cards, and smart cards are different ways to move money when you make a purchase. However, having more credit cards or debit cards does not change the quantity of money in the economy, any more than printing more checks increases the amount of money in your checking account.
A debit card is an instruction to the user's bank to transfer money directly and immediately from your bank account to the seller, just like a check. However, it is checkable deposits that are considered money, not the paper check or debit card.
Although you can make purchases with a credit card, it is not considered money but rather a short-term loan from the credit card company to you. When you make a credit card purchase, the credit card company transfers money from its checking account to the seller. Until you pay the credit card bill, you have effectively borrowed money from the credit card company.
Smart cards can store a certain value of money which can be used for purchases. However, some smart cards are limited in their use, only allowing certain purchases or use in specific places.