Rust is something you don't want to compile on a low-power device. But it's totally something that will happily cross-compile for a low-power device. Many people use Rust for such reasons as high-performance code and low resource footprint of it.

Frankly, you won't run GCC on an MCU either.

But if all you have is an RPi, you can still run the Rust toolchain right on it, if a bit slowly; e.g. https://opensource.com/article/19/3/physical-computing-rust-...