Often times it's more about compatibility with existing libraries or programmers experience then about speed.

I often feel that many very experienced C++ devs have fallen into one of tree fallacies: The sunken (learning) cost fallacy (I include sentimental attachment here). The speed fallacy. And the being totally hypnotised/fascinated by C++-complexity fallacy (I include the you can turn C++ into whatever you like fallacy in this one).