> Julia is great for explorative programming, while Python et al are better suited for slightly more structured, more productionized programming

In Julia, explorative programming is productionized programming, you don't have to switch to a different or restricted set of tools to make your program fast, it's the same code that you can profile on the fly. With types, you can patch your hotspots by adding a specific method to the generic function, and it will get invoked automatically instead of the more general case algorithm.