My issue is that you can still have a nice readme (often even giving a better, brief overview) by sticking to HTML-free Markdown.
Gitlab seems to be slightly better than Github, by allowing things like badges to be listed outside of the README, in the header of the repository page.
This always irked me as I can't read the image when trying to look at raw text and the, say build status, isn't actually relevant to understanding the project. Sourcehut has an interesting approach where you can POST any HTML to an endpoint at it becomes the homepage. You can tag on extra markup if you want in the build step and that markup doesn't have to live in the README (say badges, other images, abbreviation tags, summary/details, etc.)
* reading documents in the terminal (like man pages)
* note taking
In both those instances the less auto-formatting that the editor does the easier it is for me to use the use the file format.
I’m sure you can say that editor auto-formatting isn’t an issue because people manage fine on MS Word. But the point is I want as little distractions as possible when not taking but I also want to be able to add headings and code snippets. So wrestling with an editor when it gets its formatting rules in a mess is the exact opposite of productively. Eg take a look at the number of authors that still use DOS editors for similar reasons.
The examples shown in the fine article are Hello, world. The information contained within would be just as clear in vulgar prose. However the Mermaid code to create complex flowcharts that are not easily described in words, would be just as opaque as the Netscape 5 codebase.