The example is good, I just dont understand why you focused on compiler performance or developer experience. It doesnt imply program's performance.
We were talking purely about performance/energy eff of generated binary, not other RELEVANT things like developer experience/low compilation times because it is outside the scope of this discussion.
Yes, C++ is poorly designed language, but point that syntax (letters) don't imply language's performance stands. The result is up to the implementation: compiler, runtime/vm, std libs, etc.