If they had just followed through in the 1970s, I’d only have to use one set of tools for repairs and keep an imperial set when I’m reconditioning old equipment. The UK has the right idea - imperial where history and culture matter: beer should be served in pints, not 500 ml/ half-liter; metric where measurement actually matters like woodworking, machining, framing, science stuff, etc.
I have to use both sets of wrenches and socket tools for my vintage Datsun (Nissan) cars from the 1960s and 1970s. Half the car had metric bolts, and half the car had U.S. measure bolts. Some engine components were originally derived from British designs that were licensed by the Japanese for their engines way back then and were metric. They adopted U.S. measure for body and some engine components.