In my view, MarkDown is a great kernel for what one could call "structured writing", while LaTeX is a great exploration of, and ecosystem for, the entirety of technical writing. I see both as points of departure to finding the best approach to write 21st century technical documents. More details on that opinion at [1].
This is also part of the fundamental mission of Authorea, where we offer support for writing all of MarkDown, LaTeX and RichText today, while working hard with the larger community to arrive at better tools in the long run.
Anyhow, there are non-trivial trade-offs in making these choices, and I personally find it exciting to see where one can reap the best returns.
[1] "LaTeX is Dead (long live LaTeX)" https://www.authorea.com/19359