Maybe the author uses a CMS that's supposed to replace tags like [happy-face] with an emoji, but something broke?

??? This isn’t on the linked page.

I don't think I've ever seen someone do this from both sides of the same abbreviation (eg. Automated ATM Machine) before now, that's quite amusing.

The Extended Keyboard II came with a plastic overlay for the function keys. It showed Cut/Copy/Paste for F2/F3/F4 respectively. See https://chrispeak.com/2022/04/08/apple-extended-ii for a photo.

Not sure if this was ever supported system-wide in any way, though.

Having seen laptops with dedicated copy/paste/undo/redo keys, I think Apple can be forgiven for not going down the function key rabbit hole: https://pomelo.shockfox.net/pub/img/powerlite.jpg

(Yes, they could have just replaced the "regular" function keys with copy/paste keys, but I feel like that would have gone over about as well as the various times they've, uh, tried to replace the function keys)

ASCII is a 7-bit encoding, so adding more symbols to it would rather defeat the point.

Once you already had that encoding established, in a time of 8-bit computing for which it had a practical purpose, it's historical momentum and inertia from there. Sure, we have Unicode now, but getting the entire industry to settle on including a sparkle emoji and a fire emoji on keyboard layouts is probably not going to happen.

ASCII is 7-bit and fully filled out. Every other extended character system prior to Unicode was sporadically supported. C has digraphs and trigraphs because even the ASCII punctuation wasn't guaranteed to be available on all keyboards. IBM, notably had an APL typeball for their Selectric derived terminals but that was equivalent to switching character sets and not something that could be considered universal prior to Unicode.

Enter appropriated the same “arrow returning” symbol long ago, and the key is colloquially known more often as Enter these days.