> can't do the gymnastics with pointers that C can

It can if you write the "unsafe" keyword, but there's a pretty strong community norm around not doing that sort of thing, unless you can encapsulate it inside some sort of safe API. And to be fair to C, I think C can close the gap with Rust/Fortran if you use the "restrict" keyword a lot?

With unsafe, you can do anything that C can.

Without unsafe, there’s significantly more aliasing information, which helps optimizations.