I've heared Americans, unironically, state that the metric system is less precise than the imperial system.
I have no clue what the origin is of this myth, but at this point I wouldn't be surprised if Trump held this belief too.
> origin is of this myth
poor education system
Depends on the field - it happens that 1\1000 inch is a good tolerance for many machining operations, while metric doesn't have a convient round number close enough to that range to be useful. That doesn't slow down mathinists though, they know the fraction of mm tolerance they need to use and it is what is marked on their tools.