I've worked in the payment industry and among other things built a payment terminal, so I know a thing or two about it.<p>1st: The message overhead during communication is not an issue. It is tiny compared to the time it takes for the credit card to do it's crypto thing.<p>2nd: This won't be adapted ever. There is simply way to much working infrastructure out there build on the APDU protocol. And there are so many companies and stakeholders involved that doing any change will take years. If they start aligning on a change, it would be something that makes a difference, not something that safes time in the order of 5 to 20 milliseconds. per payment.