Not only that but Markdown use the conventions people already used in text files (point 3 in the article). People wrote Markdown before Markdown existed, they just formalized it.
In fact, I like to write notes and documentation in text form, and then I notice I have been using Markdown all along, so I rename my text file into .md, fix a couple of markers, and now it looks nice on a viewer that supports markdown, and I have syntax highlighting in my text editor.
BINGO. a key point he either is ignorant about or strangely chooses to overlook
> Not only that but Markdown use the conventions people already used in text files
So why not Markup? At the time, everyone was using markup because Wikipedia was in wikimarkUP, with # for numbered lists, {} for macros and === to denominate titles. The latter still works in Markdown, but the former doesn’t. Funny heritage: Confluence shortcuts are also expressed in markup because it was the trend at the time, but they changed the shortcuts when they went to the Cloud.
That's the main reason I still like writing Markdown (and Typst nowadays as well); I can "render" it in my head very quickly.
When I'm reading Markdown, I almost don't even see the symbols. Beginning a statement with a # immediately just looks like a heading, surrounding a word with asterisks looks italic to me, wrapping a string with backticks looks like code formatting to me, and my assumptions are generally right so I don't need to render very often (which is why the Pandoc -> LaTeX -> PDF pipeline didn't bother me that much).
If I'm writing LaTeX or something, I generally have a very rough idea of what something will look like, but it's not terribly reliable for me. I need to render frequently because my assumptions about how something is going to look is likely to be wrong.
I mostly use Typst now because it is similar enough to Markdown, and the compilation time is so categorically faster that I see little reason not to use it, but I still respect the hell out of Markdown for popularizing this kind of syntax.