Why does a retailer give the options of either a credit or debit charge when using debit card at time of purchase?

There are some people who prefer to use their debit cards with the credit feature. In some cases, it is safer to use the card as credit because one does not have to enter a PIN. Such places as gas stations and convenience stores are much safer this way, simply because scammers cannot use your card number for a debit card without a PIN.