I meant the metric system as a subject in isolation. You can do scientific experiments bake a bread, hatch out eggs, build a house tailor a jacket and make CAD drawings for a CNC machine.

Metric system does it all and you can corroborate with others and have the plan come together with precision.

Abstractions are frequently more powerful tools than physical ones.

Just look at language and Bitcoin. You can't prove it is real but you know it's there cause it just works so darn well.