Related: Fake explanation, Guessing the teachers password, Understanding your understanding, many more
The mental model concept gets used so frequently and seems so intuitively obvious that I debated whether to bother writing this. But beyond the basic value that comes from unpacking our intuitions, it turns out that the concept allows a pretty impressive integration and streamlining of a wide range of mental phenomena.
Added to the Wiki.
You should've waited for the article to get promoted, and it seems it's not going to be. Currently, the concept is not clearly explored or motivated on the blog.