Sorry, let me rephrase in the way that I did in another comment: it seems that to be a codepoint, it needs to be useful in plain text scenarios. Emoji are usef

Sorry, let me rephrase in the way that I did in another comment: it seems that to be a codepoint, it needs to be useful in plain text scenarios. Emoji are useful (arguably I guess) in plain text scenarios because they exist to convey additional information about an author's emotion, and that author might use plain text. The external link symbol is not useful in plain text scenarios because it exists to convey additional information about an author's preceeding hypertext, and that author isn't using hypertext.