The chief advantage of the more expensive cards over the ID-only MIFARE cards is that you can store data securely on the card, so it can be used without a netwo

The chief advantage of the more expensive cards over the ID-only MIFARE cards is that you can store data securely on the card, so it can be used without a network connection. This helps if there's a network outage and reduces transaction time. That said, it's super common to see recording done on both the card and on the network -- as you note for GoCard and Opal.