The benefit is that you and other Rust developers could potentially implement improvements to FFMPEG. Again, if you stick to porting only the top layer of FFMPEG - the media processing framework with the CLI - you can still keep the rest as C and link it all together in a build. Your Rust version (and any improvements implemented by other Rust developers who contribute to wedeo) can easily be converted back to C so that patches could be offered back upstream to the main FFMPEG project.
As for the updating, this is something that I’ve been considering but it’s obviously not in scope until `wedeo` is fully featured. But yes, this is something that LLMs should be able to do quite easily, it could even trigger on every commit.