Because a personal loan has a fixed rate, using a personal loan for large purchases usually makes more sense than using a credit card, which has a variable rate. An exception might be if you have a card with a low introductory interest rate that is lower than the personal loan rate. In that case, using your credit card might be better.
Additionally, credit card payments can vary from month to month, making it hard to save money and pay off your debt. Personal loans have fixed monthly payments, which means there will be no surprises on how much you owe each month.