It's a model. Like all models, it's wrong as soon as you delve into the details. Under certain circumstances it can be useful, though.

The reason INTJs seem to be disproportionately drawn to it (actually, like most statements, that's inaccurate - in my experience INTJs and INFJs are most drawn to the MBTI, followed by other N types...which is what the theory would predict) is because INTJs like to make systems and models of how reality works, and MBTI is one model of how psychology works. Any halfway-mature INTJ (or person, really) will recognize that the model is not reality, and that once you dive into the details, you'll find numerous ways where the facts don't line up with theory. But as a tool for orienting yourself, it's a handy first approximation.