With a debit card, the funds are taken from your bank account right away so if someone has access to your debit card, they can withdraw your money almost instantly leaving you with a "0" balance.
If someone has access to your credit card, yes they can make some great purchases but, because there's a period of time before paying off the debt, the fraud is easier to spot and limits your liability.
Debit cards make sense if you need some cash - you withdraw at an ATM, if the machine is on your bank's network, there's usually no fees and you're good to go. If you use a credit card at an ATM for cash, you're basically providing yourself with a loan and if you're only paying the minium balance on your monthly credit card statement, your cash advance is now costing you money when you factor in the cards APR rate.
