[newaccount74]

I just returned from a trip in Asia where 50% of machines did not accept any of my cards. In one case (parking garage) I asked a passerby to pay for me with their card, and gave them cash.

While I enjoy that I can pay everything by card at home, and mostly stopped going to the handful of places that don't accept cards, I do appreciate the fact that cash is usually available as a backup.

[londons_explore]

Many American credit cards don't support some of the security features required in other countries. For example they might not support the card itself knowing your available balance so that small transactions like parking can be done entirely offline, and the parking garage collecting a cryptographic proof from your card that you have $3.50 available in your account. Remember that to do this, your card has to offer such proof in whatever currency the parking garage uses.

[singron]

How can this work if you have online or recurring charges? It seems like a lot of work to still not know the balance.

[londons_explore]

It isn't a perfect system. The bank guarantees they will pay for any charges that the card digitally signed, and the bank will take any losses.

Most banks typically authorize the card to make ~$150 of payments or so offline. Anything bigger, or for risky customers or those with a low balance, it needs to be an online transaction.

The benefit of offline transactions is they can be done in under half a second, compared to the 5-10 seconds online transactions take. For things like opening the barrier in a car park, 10 seconds is too long.