But you can't do that with Transcrypt, either. Both are "not quite python" and won't run regular python code. There is very little difference between the goal of the two projects.
Edit: Within reason. Anything involving the sys module is out, since there's no system to back it.
There's also the fact that everything is still, at the core, pure javascript. For example you can't print("string" * 10) or even iterate over a dictionary.
I'm not saying this to put down the project - I am very interested in it - but it cannot parse pure python, and that isn't the goal of the project.
You're right, it's not there yet, and I'm interested in it for purely theoretical reasons (I personally don't think I'd ever use Transcrypt for anything in production), but I think it holds great potential.
[1]: https://github.com/pybee/ouroboros/tree/master/ouroboros