If you are traveling and need to rent a car in the airport - sometimes it is not possible to do without credit card. Otherwise you don't need a credit card.
Using a credit card makes it way, way easier to rent a car or book a hotel room, or do other transactions that require a significant preauth.
If you present a debit card to one of those desks, they may encourage you to swap for a credit card. Because a debit preauth ties up actual funds in your account. A credit preauth costs nothing but part of your credit limit. It really is a difference if you expect to spend money on vacation.
