Hi author here!
It was more a play experiment than a true try to replace Python/Ruby/Go scripting. I was very intrigued by "Objective-C Minimalism" http://bou.io/ObjectiveC-Minimalism.html and wanted to see what would be scripting in Objective-C with all new features (Objects literals, ARC etc...)
So I am not surprised someone is trying to use it as a so-called shell script. The cocoa frameworks really contains a lot of convenient API (ex. when it comes to python, you have to install PIL or something else to process images). But on the other hand the objective-c shell scripting can not be used on platform other than OSX. That is a disadvantage.