I've advocated for a different approach.

Most of these "rich formats" are, let's just be honest, Microsoft Office file formats that people aren't willing to give up. But these aren't binary formats through-and-through; the OOXML formats are ZIP archives (following Microsoft's "Open Packaging Conventions") that when extracted are still almost entirely simple "files containing lines of text".

So rather than committing your "final-draft.docx", "for-print.oxps" and what-have-you to the repo, run them through a ZIP extractor then commit that to the repo. Then, just like any other source code repo, include a "build script" for these—which just zips them back up and gives them the appropriate file extension.

(I have found through experimentation that some of these packages do include some binary files (which I can't recall offhand), but they tend to be small, and you can always come up with a text-based serialization for them, and then rework your build script so it's able to go from that serialization format to the correct binary before zipping everything up.)