offer more filetypes?

[mastef]

Since unoconv can handle a lot of conversions - e.g. ppt -> pdf or pptx -> pdf ( from http://dag.wiee.rs/home-made/unoconv/ ), any reason to not include them from the get-go?

[leplatrem]

No, we didn't avoid those at all. It's just that this tool was driven by our use-cases in Geotrek.
Feel free to contribute this enhancement, add yourself to authors, and we'll happy to review it and merge !