Author here—Two reasons, mainly. HTML+CSS is a great layout engine, and Eleventy is a good tool for making development more pleasant. While I have a lot of experience using other tools, e.g., LaTeX, I think they're not as well suited to laying out simple documents.
Disagree. A resume needs to be a professional-looking document, not necessarily a simple one. LaTeX is much better as the primary format, with plan text and html serving as backup.
Thanks for sharing all this btw, I've been wanting to find a good static site generator that fits my needs and this actually led me to it!
You are giving me “how” and I was asking “why”. No biggie but don’t really see why