And it's not just inefficiency. Even with fancy FFI generators like PyO3 or SWIG, adding FFI adds a ton of work, complexity, makes debugging harder, distributio

And it's not just inefficiency. Even with fancy FFI generators like PyO3 or SWIG, adding FFI adds a ton of work, complexity, makes debugging harder, distribution harder, etc. In my opinion in most cases where you might want to write a project in two languages with FFI, it's usually better not to and just use one language even if that language isn't optimal. In this case, just write the whole thing in C++ (or Rust). There are some exceptions but generally FFI is a huge cost and Python doesn't bring enough to the table to justify its use if you are already using C++.