Weight is a measure of worth in oh, so many ways. Elementary balance scales were being used in southern Asia 5,000 years ago. Spring scales didn't come into common usage until the mid-19th century, at which time they promptly became indispensible on farms and in retail shops among other places. Accurate electronic digital scales are a child of our own time, not much more than 20 years old. Though many chefs and home cooks scorn precise measurement in preparing food, scales are essential, for presumably obvious reasons, in commercial food production and in baking (even at home) — and are also required for the realization of most so-called "molecular" creations.