The only reasons I can think of is petty fanboy reasons. Rust solves most problems and will make the world a lot safer. There's no reason to start new projects in Go, C++. C#, etc, is there?
Different langauges have their uses. For most of my programming I use Unicon. It gives me most of what I want - there are things that are not available in it, but I can live with that. The fact that "failure" is an option makes many of my projects simpler. Not having to concern myself with booleans for coding purposes is often refreshing. But that's just my take on it.