Maybe I'm just naive, but whenever someone says "systems language", I think "ooh, something better to write kernels in?" I guess I'm waiting for something semantically equivalent to C, but with better options for macros and code generation, and some compile-time guarantees. Just less tedium, more DRY.
I don't actually program C, I just have projects in mind where it seems like that's the best language, where performance and compatibility with other languages is important. But C seems like such a pain to program in that I really wish there was a better option.
Rust has an unsafe sublanguage you'll probably be interested in.
That said, writing kernels is explicitly not a goal of Rust. It may well work great with a custom bare-metal runtime, but we aren't letting the needs of OS kernels constrain our design space at this time.
Honestly, I feel like people are too scared of C, and sometimes I think that derives from ignorance about systems (and not quite the type of systems Rust is supposedly dealing with, I don't think; but I didn't finish the slideshow). Read CS:APP; you'll learn C and systems at the same time, and see why C isn't so scary after all, but systems are. (This is just based on conversations I have had, I'm not assuming this would be appropriate for you, andrewflnr!)
In this case, they're looking to write a large portion of a web browser in this language. That's practically a kernel, these days, and the language looks well-suited to the task.
It's ambitious, definitely, but the world needs more ambitious things that will be amazing if they succeed.
I don't actually program C, I just have projects in mind where it seems like that's the best language, where performance and compatibility with other languages is important. But C seems like such a pain to program in that I really wish there was a better option.