I agree. And that's exactly why there exist interface languages such as JNI so you can write your higher level code in a nice language and get down to C/C++ for the time-critical parts. I don't see much of a problem here.
This introduces a whole new category of pains in the ass. You need to run two debuggers at the same time. Inverting control with callback interfaces is tricky. there can be friction between the memory ownership models in the managed and native code. And it just makes the system that much more complex. I've been working in a python / c++ interop system for a while and I think some of the c++11 features make the benefits pretty questionable.
