I agree with this - offlining transactions are a possibility for some instances, but in most cases, there is a significant difference in speed - I'm in Russia at the moment and when I have a transaction go through the terminal, my bank sends a notification of the transaction usually before the pay terminal is done with it's processing; so there must be some rapid communication happening to authorize the transaction within a short period, even if the actual transfer of funds transaction takes longer (which is expected). When I briefly returned to the US last year after the chip terminals were implemented, I was a bit frustrated to see that it did indeed take significantly longer than I was used to, neverminding how inconvenient it was to not have the ability to use the NFC or the card slot on the majority of terminals.