Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What's the difference when asked for “debit or credit” by a store when using credit and debit cards?
These are two different ways of processing payments. They go through different systems many times, and are treated differently by the banks, credit card issuers and the stores. Merchants pay different fees on transactions paid by debit cards and by credit cards. Debit transactions require PIN, and are deducted from your bank account directly. In order to achieve that, the transaction has to reach the bank in real time, otherwise it will be declined. This means, that the merchant has to have a line of communications open to the relevant processor, that in turn has to be able to connect to the bank and get the authorization - all that while on-line. The bank verifies the PIN, authorizes the transaction, and deducts the amount from your account, while you're still at the counter. Many times these transactions cannot be reversed, and the fraud protections and warranties are different from credit transactions. Credit transactions don't have to go to your card issuer at all. The merchant can accept credit payment without calling anyone, and without getting prior authorizations. Even if the merchant sends the transaction for authorization with its processor, if the processor cannot reach the issuing bank - they can still approve the transaction under certain conditions. This is, however, never true with debit cards (even if used as "credit"). They're not deducted from your bank account, but accumulated on your credit card account. They're posted there when the actual transaction reaches the card issuer, which may be many days (and even many months) after the transaction took place. Credit transactions can be reversed (in some cases very easily), and enjoy from a higher level of fraud protection. In some countries (and most, if not all, of the EU) fraudulent credit transactions are never the consumer's problem, always the bank's. Not so with debit transactions. Banks may be encouraging you to use debit for several reasons: Merchants will probably prefer credit because: Consumers will probably be better off with credit because: