Yes absolutely sure. I have spanner’s in my tool box that prove the point.
No, they are not poorly made.
Yes, they fit the nuts they are designed for perfectly.
Yes, they are marked with the same fractional markings
Yes, the sizes with the same fraction marking are different sizes.
No your example does not prove your point it just shows that the maker did not mark the spanner correctly as AF or W
Yes the auto industry has seen the light even in the USA and they use metric fasteners and have for decades.
my tool box has the spanner’s I needed over 5 decades ago to work on my Tiger 100, Norton Commando and a number of Japanese models, including a Honda CB 400 a 4 cylinder bike
i colour coded them, blue is metric, red is AF and grey is W.