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.
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.
Or is there some sort of technological breakthrough?