I can only guess regarding the use case. I still can make a statement that I personally do not think that the coolest part of a codebase should be a new general purpose language at its foundation. To me this reeks of not invented here syndrome, inner-platform effect and KISS "violations". IMO when you provide new tooling you want your developers be able to stand on the shoulders of giants and let them choose the fights they want to fight. Idiomatic programming is very helpful in this regard. When programming new languages with macros is idiomatic in Clojure so be it, but I doubt that.