... and 95% of the mankind according to internet(TM). Its always funny to read similar statements, US folks putting those systems as something almost equal in usage when exact opposite is true. Exactly same for volume units.
If for nothing else, units conversions is either trivial or stupidly complex, and everybody is doing it all the time so it makes actual difference. We used to have tens if not hundreds of similar systems to imperial one here in Europe during medieval times (my own country at least 5 of those), but we moved to much greener pastures since then and now it just looks... ridiculous to keep it polite.
If for nothing else, units conversions is either trivial or stupidly complex, and everybody is doing it all the time so it makes actual difference. We used to have tens if not hundreds of similar systems to imperial one here in Europe during medieval times (my own country at least 5 of those), but we moved to much greener pastures since then and now it just looks... ridiculous to keep it polite.