I don't understand your comment. It sounds like an argument against a process for manually creating these kinds of files, which is not at all what my comment was about. It was about accessibility, real-world engineering, and describing a file format/packaging convention.

The packaging convention I described is similar to the container formats used and created by MS Office apps. The difference is that DOCX, XLSX, etc rely on XML instead of HTML that can be used without requiring a separate proprietary app. People create and exchange those files every day (even for things as trivial as a single-page flyer) without knowing or caring about whether it should "warrant this kind of treatment". Worrying about a purported edge case for <10 MB(?) of data sounds like an imaginary concern.

My bad, I had indeed misunderstood what you were saying.