C++ is efficient. It is as close to the metal as you can get(i.e., fast) and yet have all the Object-Oriented Programming features.
This efficiency comes, not at a cost, but with responsibility. As opposed to other Object Oriented languages, you are responsible for memory management.
C++ may be harder to grasp than other languages. And this may be a reason why people shy away from it. However, when it comes to Game Engine Development, the ”user-friendliness” of a language should not be the deciding factor. Its efficiency is.