I wonder if this can get the appropriate community to make it a decent alternative compared with TypeScript and CoffeeScript - or maybe I'm missing something here?
https://github.com/jashkenas/coffee-script/wiki/List-of-lang...
For many of the offerings in the list, the problem, IMHO, is the lack of a complete story.
If you base it on an existing language - in this case, Python - you would expect a full implementation of the language, or at least a good portion of the core language features. The benefits of an existing language are often familiarity and the potential to reuse existing code. With partial implementation, you can hardly gain these. And the downside of extra abstraction quickly outweighs any superficial perception of familiarity.
If you create a new language, you have to strike a good balance between language features and interoperability. You need to bring enough new things to the table to make it worthwhile to learn, adopt and support it, and yet you can't overstate the importance of a good interoperability story unless you can afford to completely ignore the JavaScript ecosystem. See DART.
Because as cool as the project is (from a scientific perspective), ultimately it will end up not being used by anyone. Most developers and companies who build production grade software for a living stick to true and tried technologies, vs. fancy esoteric stuff like this.
Don't get me wrong, I am not knocking this project and the person who created it, I am just stating the obvious reason why things like this rarely take off.
In the end, it was hard to replicate 100% of the usefulness of JS through python and convert python's cool features into JS.