I do both python and C++ in my job. They're both great at what they do IMO. Often, they are a good match for each other; several of the boost libs have been designed similarly to python equivalent. boost python also makes writing python extensions very easy.
For other reasons to write in C++ (or any static typed lang), I'd add type dispatching: calling different methods based on type. I also hate having a typo in a method name throwing at runtime.
I also often convert python implementations to C++, often using boost, usually for performance in one part of the code. You can quite often get the same implementation in a similar number of lines, especially since C++11 with boost.
For other reasons to write in C++ (or any static typed lang), I'd add type dispatching: calling different methods based on type. I also hate having a typo in a method name throwing at runtime.
I also often convert python implementations to C++, often using boost, usually for performance in one part of the code. You can quite often get the same implementation in a similar number of lines, especially since C++11 with boost.