What is the advantage? I'm neither an iOS or ruby developer, please enlighten me. It seems like this gives you a different language syntax to access the same libraries with no additional abstraction. It doesn't seem like it would speed up development much.
What I really like about it is that it allows me to do everything from the command line.
I can edit the ruby files in vim and then just run the rake task to open up the simulator to test the changes I just made.