Credit card use is most appropriate for security when making online purchases. Credit cards provide an additional layer of protection against fraudulent transactions when making purchases online, as credit card companies typically offer zero liability for unauthorized purchases. Using a credit card can also help with tracking and disputing fraudulent transactions.
Credit card use is not appropriate for purchasing a car or a home, as these purchases typically require much larger amounts of money and would be better suited for a different type of financing. Using a credit card for non-emergency expenditures can also lead to accumulating high-interest debt and overspending beyond one's budget, which is not a financially responsible practice.