I read the name "Have" as "Haxe" [1] and thought it was a subset of their cross-platform toolkit. I cannot think of many use cases (a transpiler for a system programming language) because Go in itself is very simple, which is one of the main reasons so many developers from other communities have switched, because with a short list of reserved keywords, C-like syntax, and simplicity of its standard library people can do amazing things.
At least it will provide Generics [2] ¯\_(ツ)_/¯
Would you use a project like this? If yes, for what?