Depends. they are designed so the whole units are easy for the common things you do with that size. this is a common case for things will still do today like we did 200 years ago (like build houses). But even in those areas a lot of things are not round units.

When things are not nice round units though both systems are equally hard. This is common in the modern world where we do a lot of things impossible 200 years ago.

in reality you almost never calculate on the job. You measure what is on the print and anything not on the print is figured out 'when you get there' by measuring the space left when you get there - which also corrects for previous measurement errors