Lest I come across as grousing without contributing to the discussion, let's take a peek at the author's main point on hidden costs.
Most of the argument revolves around objects. There are two ways you can run into "hidden" surprises with objects in C++ that the author is pointing out. One involves failing to use the language features given, the other involves writing some seriously odd code.
class C {
public:
/*explicit*/ C( int ); // Adding explicit avoids hidden costs
// This combination (or something like it) is lethal.
C( int, double );
operator bool() const;
};
So for the author's code to have hidden performance concerns, they would need a constructor taking two parameters of the proper type and an automatic conversion operator that converts to a type assignable as their result. Basically, the stars have to align right
and you have to knowingly write some dangerous code.
Don't get me wrong, you can hide costs pretty easily in C++ and write some atrocious code. But usually this issue is alleviated by following basic best practices. The hard part is knowing what those best practices are.