I suspect you live in North America. If so it would make sense that it is easier to use the, what did you call it, “American Customary” system. It is the native system of measurement here. I have lived in the good ol US for most of my life but I had zero issues with using the metric system when I lived abroad for 4+…

True.

180 CM is 6 feet (180 divided by 2.5 = 72)

Yes. Metric system is far superior for exact measurement. As a matter of fact, it’s better at everything

Do it. He is much more beatable nationally.