For the majority of mechanical engineers who leave Europe to work in the US it is helpful to have a good command of the metric/imperial conversions. You are not so likely to buy much lumber but just about anything else you need in terms of materials be it beam or sheet metal, fasteners, hoses, workshop layout, power connections, standards, safety regulations, contractual documents and most important interface definitions are likely to be written in imperial units. This goes down to paper sizes, drawing conventions, patents, product specifications, sales literature, legally required documentation, tooling and anything else that you meet as a physical object and the documents describing it.
If you are in education for instance in Germany you do not really appreciate how much it helps that the science and the industry use the same units. In the US most local products do not have a metric specification because they do not need one and it costs money to make one. Only foreign products need dual specs. So going over for a course which deals with industrial practices you should use the same criteria as an engineer going to work there. It helps to avoid problems further down the road in a career.