Asciidoctor renders AsciiMath to MathML [1], I imagine that it's a fairly common target after MathML (Core) was revived from the dead. While MathML is pretty verbose to write by hand, I think things like AsciiMath and LaTeX are on a different level of abstraction. You can't embed AsciiMath directly in HTML in the same way that you can't embed Markdown directly in HTML.

1. https://docs.asciidoctor.org/asciidoctor/latest/stem/asciima...