Earlier quoted context omitted.
If you are comparing Word and Markdown to LaTeX I think it's clear you haven't really used LaTeX.
Oh get over yourself. Every one of the criticisms he levelled against latex is spot on, and you pick up on the fact that he mentions Word is easier to use (which, by a long, long way, it it).
Definitely initially for simpler.
But what about using it collaboratively, merging changes and comparing between versions? Especially large documents with a multitude of authors combined later (think journals).
What about documents with programmatically generated content?
What about consistent formatting for your documents?
What about when Word gets confused by some element in the xml not visible to you?
Sure Word may be easier but there are limitations to it's use.