I see your point about variations on English, but it is actually more than an accent. The whole interface adjusts to have what I see as “correct” spellings. The voice in the car is completely separate. Still we definitely also set the voice to british because why not have your car match the stereotypical british chauffer.I remember when German cars bought in the US had buttons and knobs labeled in German. That was decades ago, but how spoiled we English speakers have become that we must have our own accent in our cars I get it though. I tried setting my Siri to English English for a day and that’s all it lasted.