You're proving my point exactly. The imperial system is so convoluted that even people that INSIST that EVERYONE should use it, don't understand its units.

Just because most people don't have to deal with a certain conversion, doesn't mean that none do. There are enough engineers that design stuff which is related to problems on these variations in scale. They waste hours in productivity in needlessly complicated conversions (because fractions). Not to mention the mistakes that get introduced like the famous Mars lander that crashed because of imperial unit conversions.

Not only are the units incredibly inconsistent, you also have the issue that Brits and boat people use variation of some of the same units. US Gallons vs British Gallons, mile vs nautical mile. MPH, vs knots. That barley corn that Holzkohlen mentioned defines shoe sizes, unless of course, you don't wear shoes.