The phrase "What has semantic HTML ever done for us?" is a riff on the quote "What have the Romans ever done for us?" from the movie Life of Brian, about a Jewish-Roman man mistaken for another Messiah.
The Romans are, of course, Italic peoples.
Italic type is derived from a form of semi-cursive writing, and is entrenched in the European printing tradition. No punning with Italy intended.
So what does it mean if you have <i> around Chinese, or Devangari or what have you? Do you just apply shear to make the text slanted?
I suspect that it bothered some "woke" types that HTML contains Euro-centric typographical directives, so they have been repurposed to have some sort of, culturally neutral semantics that is more inclusive of the planet's diversity (pardon me if I'm not nailing the terminology here).
In short, <i> no longer belongs to whitey and his writing system.
There's actually a tag for this. I can't remember what it is, but it puts dots above the ideograms, which serves the same function.
https://en.wikipedia.org/wiki/Ruby_character#HTML_markup
With CSS `text-emphasis` we can do the dots you are speaking of:
https://css-tricks.com/almanac/properties/t/text-emphasis/
Probably there are other useful bits of HTML/CSS for Asian languages. (right to left and/or vertical writing, anyone? I always wanted to fart around with pretty-printed Chinese poems and, like, calligraphy script fonts with procedurally generated jitter.)
Edit: there are also Unicode entities for these:
Actually, yes! <i> is still defined in the standard to use the italic font style: https://html.spec.whatwg.org/#phrasing-content-3
And if there isn't an italic version of the font (often the case for Chinese etc), https://w3c.github.io/csswg-drafts/css-fonts/#font-style-pro... says the browser should programatically shear it:
> If no italic or oblique face is available, oblique faces may be synthesized by rendering non-obliqued faces with an artificial obliquing operation.