It's a bad thing because as it turns out, feet are all kinds of sizes, vary over time both in individuals and in groups, and may have different sizes or averages in different geographical areas. Even the unit foot is different between Indian survey feet, US survey feet, and apparently the international foot. To add extra confusion, there's the ISO 2848's "metric foot" which is exactly 30 cm, which supercedes former "metric feet" of different lengths. If you take old feet into account, a feet can be anywhere between 25 cm and 33.5 cm. What a mess!

A standard foot corresponds to EU shoe size 48 - woe be upon the person who goes shoe-shopping with thus Goliath feet.

Then there's the randomness on how super- and subunits seem to be randomly defined (1 foot apparently is a third of a yard (which is a stupid unit name in itself, because otherwise, yard defines an area, which is much larger than around a meter), but 12 inches.

This being a stupid situation is something Europe has understood already in the 18th century, which led to unifying to rational - metric and eventually SI - units.