This sort of argument is odd to someone in a country which uses both, where a yard is intuitively "a bit smaller than a metre", a pint corresponds to a pint glass or "about half a litre" rather than anything meaningful and I'm aware that a rod and a furlong are things but have absolutely no idea what they correspond to. A foot is comfortably bigger than the average foot size, and an inch really isn't an easier unit to approximate than a centimeter

One meter is about one long step for an adult. To approximate the length of a field, you just walk along it with big steps and count. It will not be correct, but pretty close. A cm is a little bit smaller than the width of your index finger. It's all bout what you are used to. Metric doesn't "fly over people's head" where metric is the standard way to measure things, but inches, feet, gallons, pounds, miles fly over our head because we are not used to it so don't have any frame of reference.

A meter is _exactly_ square root of area of A0 paper.