Briefly describe the three credit card users

What will be an ideal response?

Answer: A credit user generally carries an unpaid balance from month to month. Most credit users don't use the grace period, and the annual fee pales in comparison to the amount of interest they pay annually. If you're a credit user, the most important decision factor is the APR, or interest rate, on the unpaid balance, because it will be the largest credit expense you face.
A convenience user is someone who pays off their credit card balance each month, so the interest rate is irrelevant. Convenience users look for a credit card with a low annual fee and an interest-free grace period.
A convenience and credit user is someone who generally, but not always, pays off all of the balance each month. Their ideal card is one with an interest free grace period, a low interest rate on the unpaid balance, and no annual fee.