Rust doesn't have a runtime so it looks just like C in compiled form. c-bindgen even spits out a c header. I’m not sure what skipping C practically means even if you can argue there’s a philosophical skip happening.
You can't apply all of the hacks C programmers apply, like calling private methods, because Rust's internal ABI is different in some annoying spots.
Of course you shouldn't do that, but it's a problem rust-to-c conversion would solve.
Another reason I could think of is the desire to take something licensed in a way you don't like, written in Rust, for which you'd like to call into the private API in your production code, but don't want the legal obligations that come with modifying the source code to expose the methods the normal way.
I don't think either use case is worth the trouble, but there are theoretically some use cases where this makes sense.
It's also something I might expect someone who doesn't know much about Rust or FFIs outside of their own language might do. Not every language supports exporting methods to the C FFI, and if you're coming from one of those and looking to integrate Rust into your C you might think that translation is the only way to do it.
Most likely, it's a way rust haters can use rust code without feeling like the "other side" has won.
