Don’t know what that is, but calling any kind of “bread” with stuff on it or it it a sandwich works for me. Where he went wrong was implying pizza is “just” a sandwich. A good sandwich is not “just” a sandwich.
Char-su is Chinese BBQ pork, in this case, it resembles pulled pork with a really sweet sauce. Bao means “bun” specifically a steamed bun. So pulled pork in steamed bread.
They take the dough and place a dollop of pulled pork in it. Then steam the bread so that as it rises the juices of the BBQ become infused in the bread. Holy cow is it good if it is done right!
If the Chinese have any right to call themselves a great civilization it is because nobody, anywhere does better roast and BBQ’d pork than the Chinese. There are others as good, nobody is better!