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.
(Non rhetorically, I think you are right but) What predictions does this make that differ from what we would predict if the brain didn't particularly like recycling?
Kaj recently talked to us about compartmentalizing. At first glance compartmentalization seems to be the opposite of what you are saying here. How do these two concepts play together and when does each apply?
As far as predictions go, reusing concepts from elsewhere might allow you to quickly make predictions about something with limited accuracy, but have a difficult time improving on the predictions. Without recycling understanding might take longer, but ultimately allow for more accurate predictions. Recycling seems to favor good enough solutions.
The compartmentalization parallel is interesting - I'll have to think more about it.