More accurately, this is one of last artifacts from ISO/IEC 646 which allowed several punctuations to be replaced with local characters in domestic variants. Cu

More accurately, this is one of last artifacts from ISO/IEC 646 which allowed several punctuations to be replaced with local characters in domestic variants. Currency characters in particular commonly replaced # or $, but East Asian variants instead chose \ and that got stuck in their own multibyte character encodings.