I'm agree with you and aware about the fact that the Fibonacci metafunction is not a good example of real metaprogramming (Computing Fibonacci series using tmp has no much sense). I only picked that example because its recursive structure is pretty well known (Is one of the most common first examples used to teach recursion), so fits well to show people how a complex template is instanced, which is the idea of that part of the post. Compare that with using an instance of std::vector, for example. Is a much more realistic example, but people usually doesn't know about the inside of a vector and how it's structured internally. The main objective of these posts is to explain tmp in away that everybody understands it well. When we all are well covered about the basics, we will can get into more complex and realistic cases in depth. That's exactly why more complex examples included in the post, like build_string, are not explained in depth. Are more a proof of concept.