Honestly, I wouldn't have thought that would be an issue to the Unicode folks. They have already allowed things (emoji) that have no place being in the standard, as they aren't even text.
I feel like Apple pushed the consortium to add a ton of useless emojis for whatever their own reasons were.
According to a sibling to what you replied to, it's because the shapes of the glyphs are still under copyright by known-litigious rightsholders and the Unicode consortium doesn't want to subject font authors to that.