It's all too often I see some cargo cult-style declaration of "no more C; it's all Rust" as if that has somehow solved all problems and absolved the programmer of the responsibility for ensuring their code is otherwise safe and correct (granted, Rust does make this easier to do), and IMHO this just ends up doing a disservice both to those proclaimers and ultimately to Rust itself. To be clear, this is not a statement against Rust by any means but rather a complaint against the conduct of some of its practitioners.
With that being said, I feel I really also need to state here that I absolutely do not believe the above to be the case with the announcement here...Even to the contrary, I would say, as the name "Hubris" says it all. It's great to see Rust used in practice like this, and I look forward to seeing more of the details in the code itself!