I think its a little bit of both. Primarily it is aimed at legacy software. IMO not a lot of new code is written in legacy C, so we have a problem with having a ton of dependencies written in a way that may not be the safest or most reliable (from recent experiences). The authors suggestion is to rewrite parts of those applications that tend to be buggy (mostly I/O parts) in Rust.

I really hate to see the naysayers comment on this article without even having read it. I think the author made a very good point.