Yes, definitely. Any application that I can think of off the top of my head involves adding C code. This is not a hurdle, but would be for someone who is using Python to get into embedded programming at a beginner level. From the MicroPython documentation:
>>>Compiling the cmodule into MicroPython
>>>To build such a module, compile MicroPython (see getting started) with an extra make flag named USER_C_MODULES set to the directory containing all modules you want included (not to the module itself). For example: ...
This is not precisely for the faint of heart, but should not be prohibitive for a seasoned embedded developer. ;-)