Or anyone who has to work with Americans. Especially when you also work with other countries as well. You can't assume dd/mm/yyyy or mm/dd/yyyy blindly in either case. yyyy-mm-dd solves the issue entirely because both sides at least agree that yyyy-dd-mm isn't a thing.
It's only ambiguous to Americans.
Or anyone who has to work with Americans. Especially when you also work with other countries as well. You can't assume dd/mm/yyyy or mm/dd/yyyy blindly in either case. yyyy-mm-dd solves the issue entirely because both sides at least agree that yyyy-dd-mm isn't a thing.