> The main practical difference nowadays is that in the case of debit cards, you're out your own money for a few days, while with credit cards, the only thing that temporarily suffers is your open-to-buy/line of credit

Right, and this is GGP's main point

The risk to a debit card user in the US is higher because the money you need to pay your rent or mortgage may temporarily disappear due to fraud, and may take longer to resolve than your deadline with your landlord. When using a credit card, that risk is not on you.