This is such a long thread that I’m not sure if this has been mentioned before. 
One thing I’m appreciating is the ability to sprinkle in a smattering of HTML features.
For example the abbr element - to create flyover definitions.
Another one is that it is possible to add strike through using the appropriate HTML element.
Now, how the various Markdown processors react to this is another matter. I’m not sure how well eg 1Writer does.
(My own Markdown processor handles abbr and strike through now, but most HTML it can’t handle.)