Obviously, our currency needs to be standardized to 17 silver Sickles to a gold Galleon, and 29 bronze Knuts to a Sickle.
What would happen if McDonald's started using the metric system? How many customers would stop going because their Big Mac is using a different measurement (that they still do not know) and a large soda is also measured differently (but they probably do not know how large it is, either).
Of course, explaining it that way makes it sound like a waste of time and money.
McDonald's executives, are you reading this?!