Think about the countless examples of individuals successfully publishing papers, in a variety of different academic fields, that were intentionally nonsensical or absurd. A big part of the reason they were able to do this is because academia has turned towards excessive use of jargon and estoteric language, even when it's completely arbitrary and serves no purpose other than to try to signal 'hey look how smart I am.' But the point is that as this language seeps into papers, what is actually said becomes ever more difficult to discern and bad logic can be masked in a guise of smart sounding language. And as the fake papers illustrate, this deception works even against experts in the field, or at least related fields.

So back to metacognition. This is clearly phrased in a way everybody can understand as 'thinking about thinking.' The latter is, at worst, slightly more verbose. By contrast let's consider another fairly esoteric term such as 'cognitive dissonance.' There is really no way effectively communicate and convey the idea of cognitive dissonance, with all its nuance, in a comparably brief phrase so it makes sense to use the word. But metacognition? It's really just taking a simple concept and replacing it with a fancy sounding word.

I don't know why we do this in so many fields. It just creates artificial barriers to communication and clear conveyance of ideas.