Yes, this is aimed at the same people, I believe. Doodle in Python and then work harder on the critical part.

I think this works best when you have some loops pushing arrays of Float64 around. And worst if you'd like to pass some library a million little functions to optimise which depend on some strange data type you just defined... Cython is quite a limited sub-language. But certainly many current Julians made a living this way in the past.