Sorry but this is a sign of ignorance. Read the biography of Condorcet. Coming up with the metric system was extremely smart. In hacker terms, think of it as a beautiful, elegant fully rescursive and reentrant function that replaces mountains of ugly legacy code.
It's amazing that at the time (1790), each profession used their own measurement system. An ounce for one trade was different from an ounce for another trade. You are somewhat aware of that of course because the difference between the US and British gallon carried to this day.
Finding a way to universally cover all measurements (weight, distance, speed, etc.) so that everything is self-consistent is not committee design. It's extremely smart engineering. It removed the need for conversion constants and factors.
In hacker terms, it was a major code cleanup effort.
The fact that a foot is supposed to be the length as a foot doesn't seem like any useful advantage to me. My foot is not precisely 30.48 cm anyway.
Some imperial units are still in use outside of the British world. Inches for TVs and computer monitors and car wheels. Feet is used for boat lengths although meters is also used sometimes. Knots and nautical miles in sailing. Feet is also used in aviation.
:)