You're the one who used the analogy. Are you being deliberately obtuse?
Height is a spectrum and yes, IQ is a spectrum. "Seven feet tall" is an easily identifiable point along the height spectrum. "Genius" is not an easily identifiable point along the IQ spectrum.
It's a wishy-washy, overly emotive term that lumps certain people into an elite group which, by the popular conception of the word, you're either born into or you're not. It says more about the people who use it than the people they're bestowing the title upon. But hey, if you like the term and get your kicks seeing it bandied about, good for you. I find it trite and counterproductive.