The protections aren't quite the same with merchant issues. Notably, most situations that you attempt in good faith to resolve, purchased within 100 miles of your home are protected for credit cards.

But even if it were - most people operate one checking account, and most folks don't keep an especially large balance. If your debit card gets compromised or there is an erroneous charge, it will process up to your balance. It is incumbent on you to notice the fraud and take action. If the bad dip is today, and tomorrow morning my mortgage and other payments bounce or hit overdraft, I have a mess to clean up.

With a credit card, you're typically hitting a larger credit line that isn't fully utilize -- you may not notice the bad charge for a month, but there's no impact to you... the thief stole the bank's money.