I work in a Flask and Jinja shop, so it's not really fair for me to pass judgement one way or another without having actually spent a month using this style. I just can't help preferring the Jinja method of templates that are mostly HTML with some templating code mixed in, vs. executable code that happens to be mostly concatenated strings of HTML.
Drupal 8 still does this. Look at the core modules help functions as an example if you don't beleive it.
> This article has kind of occam's razored me, because I can't
> actually tell if the author is serious.
(I actually didn't read the article yet, but that's what it sounds like you mean here)
> I know, it sounds like one of these “duh! moments”, but I can’t think of an instance where I saw this pattern explained in some article.