[dagw]

That is really only true if you want to squeeze every drop of performance out of Cython. For the first 80% of performance gains you don't have to go that deep.

That is another thing that is nice about Cython, you don't have to learn all of Cython to be productive. Take your existing python function and just add some type annotations and you'll see real performance gains. Then you can profile your code and see what the next bottle neck is and fix that and so on.

So, yes, Cython gives you the power to manually control the GIL and the Python API calls and manage your own memory management and layout for those corner cases where that is what you need. Most of the time you can happily ignore all of that and get almost all of the speedup available.