This is the most important project for the future of Python. I hope they succeed.
N-API succeeded, so I think it is not hopeless.
I think the “single build for all architectures” is a killer feature, and new projects should hopefully adopt it just for that.
The reference count debugging is also nice.
They made the API look pretty close to the existing Python.h API, so hopefully there is some migration strategy. There are hundreds of thousands of lines of such code in CPython itself so I wonder if they will actually migrate it. It does look like it’s based on lessons from things like the vectorcall protocol so I’m optimistic.
The C API, and all of the wrappers for it like SWIG, etc. has been an issue going back decades! Although I guess you could say our expectations are higher now.