Futhermore, doing it by hand is not as simple, but still not very complicated. This just helps alleviate the boilerplate in defining pipable functions.
I'm not talking about using the pipe operator, I'm talking about implementing it. The C++ version is ridiculously complicated.
Let's compare your code with an analogous implementation in Common Lisp.
(defun pipe (val &rest fns)
(reduce (lambda (acc f)
(funcall f acc))
fns :initial-value val))
(pipe 99 #'1+ #'sqrt #'1-) which evaluates to 9.0
It may be more verbose in C++, but its not more complicated, and its definitely not "ridiculously" complicated.
> I just implemented something very similar in Common Lisp and it wound up being incredibly simple.
Maybe for you as a lisp programmer, but for me I find the lisp code incomprehensible.