> firmware

Yes, lots of firmware runs on hardware where a GC doesn't make sense. Because of limited memory and performance constraints. Sometimes having predictable timings (i.e. not a GC with pauses) is nice. I believe compiler and library support is also just better for many embedded platforms in rust.

> networking type software

Rust is a much more aggressively optimizing compiler, and thus will typically be faster, in the places where that matters. GC pauses might also be a point against golang in some places here. Rust's idioms provide slightly less opportunity for bugs in places where reliability matters (e.g. having a type system that requires you check for errors instead of just patterns that encourage it).

So there's a difference, but generally go is a good enough language for networking software and it would be rare that I wouldn't suggest that "use what you know" is more important than the differences between the languages for non-firmware network software.