If you're targeting Go to cross-compile to, why would you build the language in Rust? Keeping to the go tool chain would reduce a lot of friction for those who are using go already, which I presume is a significant chunk of your target audience.
My guess from the readme is that the author loves some of the rust features and syntax but the simplicity of having the go language and runtime take care of making it work is just too compelling. As far as the language itself, there's nothing here that you couldn't build with go and it would likely be more productive.
true rust developers will program with magnetic needle
They probably wrote the language in Rust for the same reason they wrote a new syntax for Go: they just don’t particularly like Gos syntax.