Why do you think asciidoc is better than Markdown? Serious question as quick skim over the homepage (https://asciidoctor.org/) and it looks just like Markdown with different sigils.
Markdown's great for simple readme, or if you don't need to (say) right align an image, of apply a class to a paragraph (eg. To turn it into an inset).
While I personally prefer textile (which is a deader dodo than asciidoc), they are both able to do significantly more than markdown.
I look at the problem as: if markdown forces me to write html, then I may as well use html...
(Ps: in textile "> hello world" at the start of a line sets right alignment, "=" for justified, "p.inset#my_id hello world" applies an "inset" class to the para and gives it the id "my_id". Asciidoc is similar, but I'm not familiar enough with it to write it on my phone just now)