What does this do that a .bib file doesn't? It doesn't follow a standard which is made clear even by the creators themselves: "When you put a CITATION.cff file in the default branch of your GitHub repository, it is automatically linked from the repository landing page, and the citation information is rendered on the repository page, and also provided as BibTeX snippet which users can simply copy!"

I don't see why they don't stick to the established standard and parse a CITATION.bib instead. It would be less complex, more friendly to the user, and less likely to cause lock-in.