Why do debit card companies want you to slide your debit as a credit card?

I signed up for this chase extras promotion crap. And apparently, to gain points, I can only swipe my debit card as a credit, in order to get points.





Why is this the case, and why do so many credit/debit companies encourage you to swipe your DEBIT card as a credit card and sign?





Thanks, all answers are appreciated.|||Because when you use a credit card, the merchant has to pay a fee, which is usually 3% to the bank. So...this way the bank makes more $.|||The reason is that the fees earned for debit card use are negligible. The fees for credit card use are close to 3% of the transaction.





Personally I refuse to own a debit card because you have absolutely no protection.