You can rent a car for a road trip, for instance, with a credit card.
It's harder to use a debit card when you're renting a car.
And a lot of businesses promise you discounts if you use a credit card rather than a debit card.
They're hoping you'll charge so much you won't be able to pay it back quickly. If you can't, they can charge you high interest!
The result? You didn't really save any money with their "discount."