[sumedh]

> I thought a debit card was just for withdrawing cash?

In many countries you can use the debit card to withdraw cash and make online and EFTPOS transactions. EFTPOS machines can process debit and credit cards. With debit cards the money is deducted from your account immediately or in your case at the end of the month. (but then it should be called credit not debit)

[glenneroo]

So to answer your question using your selected terminology, they are zero-interest credit cards.