> like deduct that amount from an offline transaction balance, replenishing that balance the next time it gets to talk to the issuer during a chip-dipped payment (assuming the card is still in good standing)
That deserves its own article. Where/why in the world would you need that!?
For offline support! Chip cards were introduced before internet connections were ubiquitous.
Some cards were even explicitly offline-preferring as long as there was any offline balance remaining to save on data transmission and processing bills.
There are even some fully offline chip systems around (where both terminal and card are mostly offline) that take the “offline purse” idea even further, but these are usually separate from the mostly account-based debit and credit schemes popular today, and are often getting phased out.
These days, cards are mostly online-preferring or even online only, with some merchants taking on the risk of accepting cards while offline.
Isn't it mostly obvious? Offline transactions are needed whenever a transaction is made without access to the internet. Like a train in the middle of nowhere or a flight.
Typically the POS just accepts the card, and then when Internet access is restored, sends them all out. So the merchant takes the risk of a customer using a bad card. But with smart functionality in the card, the card itself could make a determination of whether the payment should be approved.
That deserves its own article. Where/why in the world would you need that!?