It’s mostly just people like to attack conversions no one really does. Even with it’s nice easy conversions, the average person isn’t going to tell you how many nanometers are in a megameter, which isn’t qualitatively different than barleycorns in a league.
Science also just invents new units of measure when it’s convenient, light years, parsecs, astronomical units, moles, etc.
It’s mostly just people like to attack conversions no one really does. Even with it’s nice easy conversions, the average person isn’t going to tell you how many nanometers are in a megameter, which isn’t qualitatively different than barleycorns in a league.
Science also just invents new units of measure when it’s convenient, light years, parsecs, astronomical units, moles, etc.
Moles are real, not invented by science!