[dleeftink]

I think in part, it's also a case of there being some agreement on standard textual mark-up but not universally. And for good reason: books aren't journal articles, journal articles aren't poems, and heading and paragraph boundaries differ between languages.

Even practically, are sections part of articles? Or aticles part of sections in the context of a collection? Why do we need six heading levels, not four or seven? The semantic hierarchy does equally apply across publication contexts.