Earlier quoted context omitted.
I'm so happy this is (currently) the top comment and people are starting to realize measuring perf with these well tuned micro-benchmarks is a sham.
Why is it a sham? It's useful to know that x is faster. As a user of x I don't really care if the reason it's faster is it's C++ under the hood. That's really an implementation detail for me.
A while back I implemented a game rules engine and MCTS in Torch (the Lua library). The training loop spent like half of its time running the rules engine. Writing it in Python would have been a disaster in comparison. To really make good use of the hardware and spend more time in the optimized machine learning code provided by libraries, one would have to write their rules engine in some language other than Lua or Python.