Are you being sarcastic or ignorant? Weight is grams. Length is in meters. Volume is liters. For those with intelligence, syllable count doesn't matter but doing calculations on base ten does.
Perhaps I didn't make myself clear. In the metric system, there is no metric equivalent of such practical measurements as the inch, ounce, teaspoon, tablespoon, cup, pint and foot that are in the American system of weights and measurements. And syllable count may not factor when one is doing calculations, but can when communicating about them.
To illustrate my point, if we adopt the metric system, we will have to rename the game of football 30.5 centimeter ball. I'll take football--it uses a more practical measurement and it's easier to say.