so why not just use Go? less complexity - same benefits. you're basically saying it's somehow an advantage to program in s-expressions...
That's said, the project states more flexibility as a goal - specifically supporting generics. Between code generation and the cross-language compiler, writing generics (but generating non-generic Go code) should be somewhat easy to reason about.
There are many advantages to writing real world applications in a lisp.
- structured editing of source code - macros (dry, dsl's, etc) - if your Go code uses interface{} everywhere you'll probably have more of an advantage using dynamic typing anyway.