As I understand it Cobra wants to take advantage of .NET ecosystem, it's libraries and all. If you are not into .NET then I guess you are right, but if you are willing to learn .NET or are already familiar with it, then Cobra may be a nice tool. I recently had to write a small library for .NET and used F# for this (I don't like C# and didn't want to use IronPython), but Cobra could be even better fit for what I needed to do.
If you need Python on .NET there always is IronPython, which is quite well supported. I think Cobra was made incompatible with Python syntax to emphasize that it is not Python, it has different aims and philosophy - but I can be dead wrong on this, maybe it's just because author liked some syntax better...
That being said I really don't think syntax matters that much, even if it's very similar (or very different) to something you know already. I learned and use CoffeeScript with pleasure even though it's syntax is similar - but not compatible - with Python's. Given a good syntax highlighting plugin for Vim, which I use as my editor, I have almost no problem at all with switching from Python to Coffee mode - when I end an if statement with ":" it gets highlighted as an object literal and then I instantly know it's wrong. On the other hand I use OCaml and Racket for some of my side-projects and similarly I don't miss much of Python's constructs. I think it is more important for syntax to be consistent than to be familiar or similar to something. I just don't understand marketing languages as "similar to C" in syntax, who cares?
