That first claim, that it's as expressive as Ruby, just doesn't hold up to scrutiny. (I've never used Ruby much, but I know my Python, and I'm going to assume they're approximately equally expressive). In no sane Python codebase would you see copy-paste that looks like:

https://github.com/foursquare/rogue/blob/master/src/main/sca...

or

the function/tuple/product classes found here: https://github.com/scala/scala/tree/master/src/library/scala