Sure, but in a monospaced font both of those arrows would have to fit into the same small box, so 27F6 might be the full width while 2192 would be some partial

Sure, but in a monospaced font both of those arrows would have to fit into the same small box, so 27F6 might be the full width while 2192 would be some partial width, while a -> ligature would be two widths.