I don't know anyone in computer science that writes academic documents in Microsoft Word. The standard is LaTeX. It seems the author may be well behind. All markup (in any markup language) is simply text (as opposed to WSIWYG), which is the main thing the author seems to find alluring. However, .txt files by themselves give you no way to manage special characters, references, footnotes, or any other typesetting functionality.
The author isn't from computer science nor have a computer science background. Outside computer science most people moved from typewriters to WSIWYG editors, which is the natural transition if you are unfamiliar with how to use a computer.
Nowadays, when most people being digital natives or being accustomed to use a computer, it makes more sense for people to move away from analog metaphors to proper computer-designed tools.
