Most people developing GameBoy emulators these days do it as a toy project, not a serious effort to create an ultra-accurate general purpose emulator. It's like writing a raytracer or a Pong clone.
The best GameBoy emulators like Gambatte predate Rust by almost a decade and are often written in C++. Since GameBoy emulation is pretty much a solved problem there's no strong motivation to innovate in the scene.
I've written several emulators in Rust, I'd argue that it's very well suited to this exercise, but it's also not an area where Rust shines particularly. There's no complex memory management in emulators usually since most memory buffers are just statically allocated constant-size arrays that mimic the physical RAM on the console.
The best GameBoy emulators like Gambatte predate Rust by almost a decade and are often written in C++. Since GameBoy emulation is pretty much a solved problem there's no strong motivation to innovate in the scene.
I've written several emulators in Rust, I'd argue that it's very well suited to this exercise, but it's also not an area where Rust shines particularly. There's no complex memory management in emulators usually since most memory buffers are just statically allocated constant-size arrays that mimic the physical RAM on the console.