Regardless, why should a Vietnamese person be forced to restrict their password to ASCII? If you want to sell your devices in a country, the least you can do is to adopt to the local market. I get that Western cultural dominance makes this hard for some, but I think it should be the bare minimum.
It makes about as much sense to insist that everyone across the world use only US ASCII, as it makes to force everyone in the world to use only Cyrillic UTF-8 symbols. I.e. no sense at all.
I would also argue the counterpoint : why are the local markets adopting things that are barely functional to them?
As a comparison, if all Vietnamese people had three feet and three arms, would they all be walking around with two left and a single right Nike shoe while wearing a Champion shirt with an extra arm thrust through the sleeve?
At what point do customers and users realize they are responsible for giving consent?
