Just last week I needed to output a formatted document, and my choices were constrained to: HTML+CSS, Markdown, docx (OOXML), or odt (ODF).

The formatting had to be manipulable in code; the first two options were unsuitable for my use case. That left OOXML and ODF.

Both docx and odt are zip files, with XML content. Any guess which one turned out to be the better choice? I was left wondering why docx even exists in the first place.

Anyone using OOXML can rightly be regarded as stupid. There are far superior formats, and we should insist on their usage.