On the other hand, with debit cards money is withdrawn from your account when a fraudulent purchase is made, and you need to wait for your bank to complete an investigation to reimburse you. They also tend to have rather stricter reporting standards in that if you don't report fraud promptly, you might be stuck with (some) liability.
Either way you'll typically get your money back, but the hassle is much reduced with credit cards.
If a merchant posts a fraudulent transaction against a credit card, you'll most likely get your money back. If a merchant posts a fraudulent transaction against a debit card, you might not get your money back.
More dangerously, if your debit card credentials are skimmed and used to withdraw money from your account by any means other than the retail debit-card payment system, you won't get your money back.