There are different kinds of illusions. The world we see around us is an illusion created by the brain's sensory processing. But this illusion is good enough to allow us to act in the world. We don't call it illusion, we just call it the world.
If I think "I think", it is a vast simplification of processes going on in my brain, but it doesn't mean that there's no processes corresponding to my thinking "I think".
Most of the time I act as a single intelligent agent, not as a bunch of subsystems with no unifying goals. So this "illusion of consciousness", while being simplification of brain processes, falls in the category of things we usually don't call illusions.
And that's why Dennett's wording seems misleading to me.
If I think "I think", it is a vast simplification of processes going on in my brain, but it doesn't mean that there's no processes corresponding to my thinking "I think".
Most of the time I act as a single intelligent agent, not as a bunch of subsystems with no unifying goals. So this "illusion of consciousness", while being simplification of brain processes, falls in the category of things we usually don't call illusions.
And that's why Dennett's wording seems misleading to me.