That’s a fair point when the goal is to decide whether to use BP or C++ to implement something in your game. This is why I believe typically people mention in these kinds of “C++ vs BP” topics that, theoretically, C++ is faster, but it probably won’t matter for most things that people are implementing because most features that people implement have a negligible impact on the performance anyway. Any feature that is complicated enough to have a really significant impact on performance is probably gonna be too complex to implement in BP anyway without getting lost in the spaghetti (unless you’re purposefully trying to harm your performance, for instance by creating an infinite loop).
The benchmark that @ described does in fact provide evidence for this point, that you really have to go out of your way with huge numbers of actors to actually add a noticeable amount of overhead to what the engine is already doing, regardless of whether it is implemented in C++ or BP. But the conclusions as written in that post, describing a numeric value for the difference in computation time between C++ and BP, are not correct.