Lots of industries in USA are metric and keeping the imperial around for the social inertia. For engineers/scientists this works. For normal people, this works IFF there’s a gradual change. Eg: every sign that’s replaced should have both units. Every product needs to add both units in within next X years. Then they can make imperial optional after a decade or more of common signs and finally go all in on SI. But ofc no one likes a working solution. They’d rather stick to the measurement system that escaped pirates