I think being implemented in C++, this has one of the same problems Prothon had. There are no standard libraries or existing 3rd party libraries that you can use. You can't directly use Python modules, .NET libraries, or Java libraries. You have to start all over. No GUI toolkit, for example. Other languages like Jython, Groovy, IronPython and Boo don't suffer from this problem.
You might also check out LiveLogix. It runs on top of the CPython VM, so you can still use Python modules.