What is the key difference between a debit card and a credit card?

The key distinguishing factor between a debit card and a credit card is that a debit card withdraws money directly from a bank account. This means that when you make a purchase with a debit card, the funds are immediately taken out of your checking or savings account. As a result, you are spending your own money rather than borrowing, which is what happens when you use a credit card.

Using a debit card helps manage spending because you can't spend more than what you have in your account, thus promoting financial discipline. In contrast, credit cards enable users to borrow money up to a specified limit, and this borrowed amount must be repaid later with potential interest charges if not paid in full.

The other options relate to features commonly associated with credit cards or do not accurately describe debit cards. For example, offering a line of credit and charging interest pertain to credit cards, while earning rewards points is a benefit that many credit cards provide to incentivize spending, which is not typically a feature of debit cards.