There's no technical breakthrough, but it might seem novel to people in countries like the USA where offline authorisation hasn't been widely allowed on credit and debit cards for some time.

https://en.wikipedia.org/wiki/Online_authorisation

In many countries in Europe, offline authorisation is more common. Cards have had a chip as standard for over two decades in European countries, and a PIN is often used for cardholder verification.

Combined, these make the risks of accepting a transaction for a small amount of money offline very low.

The limit of what can be accepted offline is known as a "floor limit" in the UK.

This is just reenabling existing technology. Card chip already has everything required to verify the card and PIN[0], the only thing internet access is required is checking if account is not empty/over limit.

[0] That also means that after changing PIN on bank site, you have to visit ATM, so new PIN is actually stored on card - but that it only required for that offline mode.