In all seriousness everybody still probably needs to learn it in school, because the scientific literature is entirely in metric. Even papers authored by Americans and published by, e.g., the American Chemical Society, all use µg/mg/g/kg and µm/mm/cm/m for their measurements. If you don't have an intuitive understanding of those measurements, you can run into visualization problems.
In all seriousness everybody still probably needs to learn it in school, because the scientific literature is entirely in metric. Even papers authored by Americans and published by, e.g., the American Chemical Society, all use µg/mg/g/kg and µm/mm/cm/m for their measurements. If you don't have an intuitive understanding of those measurements, you can run into visualization problems.