I've made these arguments before. The lack of wide, common adoption of the metric system is a common plank in U.S.-bashing. The metric system is convenient for

I've made these arguments before. The lack of wide, common adoption of the metric system is a common plank in U.S.-bashing. The metric system is convenient for calculations involving conversions of scale or dimension (e.g. "How long is my finger, in kilometers?" "What is the rough mass of a cubic meter of water?"). The standard units are more convenient for calculations involving division, as you point out. These are convenient in different arenas and it doesn't surprise me that these different arenas use different systems. For science and engineering uses, the metric system is a lot better, and it's in wide use. For the common human-scale uses you point out, the standard units are more convenient. People often pooh-pooh the matter of "convenient" units but the fact is that teaspoons and tablespoons are still used for cooking, even in France itself. And these aren't approximations but (as they are in the U.S.) strictly defined according to a standard. The metric system makes a great standard, which is why the U.S. fully adopted it and all weights and measures are defined in terms of the metric system. The metric system is taught in schools. There's just not a compelling reason to, for common and mundane uses, to switch to it; and some disadvantages. (I always wondered why decimeters weren't more popular with metric users, they seem convenient enough. But they do seem to get by fine with piles of centimeters.)