I've seen some very impressive Julia libraries that perform almost at the level of C code, so I'm not sure if the gap that Julia needs to fill is that large.
Also, a quick question: which one is preferred nowadays, Cython or Numba?
Also, a quick question: which one is preferred nowadays, Cython or Numba?
That being said, when Numba works it's great and is much easier to work with than cython.
In Numba 0.21.0, on-disk caching of jit'd code was also introduced, which was one of the major sticking points for us to put Numba into production in areas where we needed faster start-up times. Before we could really only use Cython because we required the start-up times available only from AOT compilation.
That all said, Numba has been a bit buggy for me at times, although these get squashed pretty quickly. I've only found a single bug in Cython in all of the years I've been using it, and it's amazing how quickly Robert Bradshaw or Stefan Behnel respond and fix things considering Cython is not their full time job.
Numba is specific to numeric/array-oriented code. Cython is general-purpose and can also be used to implement e.g. datastructures.