Por que o Potterverse não usa o sistema métrico?

Em Pottermore, o post sobre Medidas diz:

Just as British witches and wizards do not use electricity or computers, they have never turned metric. They are not governed by the decisions of the Muggle government, so when the process of metrication (switching to metric measurements) began in 1965, witches and wizards simply ignored the change.

Witches and wizards are not averse to laborious calculations, which they can, after all, do magically, so they do not find it inconvenient to weigh in ounces, pounds and stones; measure in inches, feet and miles; or pay for goods in Knuts, Sickles, and Galleons.

De acordo com esta página , o Reino Unido não iniciou o uso significativo do sistema métrico ( fora do uso científico e do comércio internacional) até a década de 1960. De acordo com o tema geral de que o mundo mágico é mais lento para adotar mudanças inovadoras (eles ainda usam uma locomotiva a vapor), eles se prenderam ao antigo sistema de medição.

Fora do universo, também o torna mais acessível aos leitores americanos com menos edição.

Em suma, ela fez isso para irritar sua irmã.

Rowling explains that she insisted on using imperial weights and measures rather than metric because she thought they were more quirky and thus more suited to wizards than the cold logic of the metric system. She subsequently accepted membership of the British Weights and Measures Association, not because she is opposed to metric, as has been assumed, but as a way of irritating her sister. "Di is never funnier than when infuriated, and among her many pet hates is the old-bufferish adherence to the old ways just for the sake of them."

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