I don’t think so.

It is just realization by author that HTML is also useful tool and MD lacks some stuff.

He didn’t write anything about “now we should stop using MD files”.

It is more like: “I see I can do cool stuff with HTML and found cases where it definitely is right tool for the job”.

It feels like a word salad that's been created to hit a word target because it's also LLM generated. Really not worth spending 5-10 minutes reading some "AI" output.