the raising of numba shows us why numpy and "just write vectorize-styled code with a C++ backend" is not enough.
yet Numba basically makes your python code not python. It doesn't support so many things: pandas dataframe, or even as simple as a dict(), which means you often have to manually feed your numba function separate arguments.
To separate a complicated calculation into numba-infer-able parts and the not ones is not fun and sometimes just impossible.