It is what Dennett thinks. Actually, it's what Dennett thinks he thinks, because that idea of Dennett's is inherently non-sensical; it is self-contradictory.

Here's why.

To explain qualia as a "trick" is to void the onotological status of qualia itself. He can't do that. It doesn't matter if it's all an illusion or a trick, it doesn't matter what its ultimate epistemological status is. Qualia is experienced and it's the experience itself, whatever its biological underpinning turns out to be (you can't have sight without eyes), which is relevant.

Yes, all experience could be fallible and illusory but the fact of experience itself cannnot be an illusion.

Experience qua experience is the thing no scientific theory of perception and cognition needs. So why does it exist? In other words, why are we not as not-conscious as rocks and chemical processes and planets and electrical activity, doing all we do, saying all the things we say? It's certainly possible.

Dennett, and I am inferring this I haven't heard him say it, is an ontological positivist. Only those things which the methods of science reveal to exist are "real" and everything else is, as you say, some kind of illusion. Sonunds good. But an illusion (which is some experience whose epistemology we have misconstrued) is not itself an illusion. Its ontgological status as "a thing which does exist" is secure.