If they factored in the other-bank transaction costs, there'd be something else to "what-about." What about the company's energy costs in its non-payment processing? How about all the plastic they use to make those credit cards? The silicon in the card swipe machine?

None of these things will bridge that gap, unveiling a missing data point that somehow makes VISA less efficient by six magnitudes that somehow researchers were missing all this time. But constantly asking for more detail is a good way to stay in denial about Bitcoin's terrible numbers.