Considering the popularity of JS and Ruby as a first language for many new programmers, I could see the argument that it would be useful in the sense of getting

Considering the popularity of JS and Ruby as a first language for many new programmers, I could see the argument that it would be useful in the sense of getting them to understand basic functional concepts in a more familiar environment. Although, I agree with you: a Lisp (probably Racket or Scheme) is a much better bet for learning the functional style.