> If anything, I’d expect them to write the weirdo xml of that cursed file format directly.

Isn't this essentially what Claude Cowork is doing? AFAIK, it's running python in a VM and using stuff like xlxswriter, openpyxl, etc. at least it was last time I used it to generate some docs.

I've done that myself too when making some excel reports for management out of pandas data frames.