Earlier quoted context omitted.
> It’s so much easier to measure with a kitchen scale than it is to wonder “did I pack the X in too tight or too loose into this cup?”. Here in the UK, I get irrationally annoyed by seeing recipes that use "U.S." measurements. A "cup" is mostly meaningless to me as I've got lots of different size cups and as you state, it's not a consistent way to measure most ingredients (I can understand it being used for liquids,…
No need for scare quotes, US customary units are a thing. A US customary cup is, at least, quite standard at 8 fluid ounces. This is more standardized than the unit of measure used in British recipes and whatnot. The issues surrounding volumetric measurements for dry goods is an entirely separate matter. 240 mL of apricots is just as useless as 1 cup of apricots.
One British gallon is about 4.5 liters, where a US gallon is about 3.8. Quarts, pints, and cups follow, but fluid ounces are another thing. A US gallon is divided into 128 fl. oz., while a British gallon is 160. This results in a US fluid ounce of about 29.6 ml, vs. 28.4 ml for the British one, and also affects teaspoons and tablespoons.