No, dark energy isn’t an illusion
"The Universe is indeed imperfect, but we know exactly how (and by how much) it's imperfect. It was an interesting idea, but the effects of these imperfections is well-understood, and can't explain the observed acceleration. Dark energy is here to stay.
If you're going to resurrect an old idea, you'd better have a new reason why the old objections that ruled it out no longer apply. Until that day comes, you can rest assured that dark energy is no illusion!"
Every so often, an idea comes up in physics claiming that perhaps dark energy isn't real. The ideas focus on one of two lines of thought: either they discount the observational evidence, or they attempt to show that all the calculations are fundamentally flawed. The latter case often points to our Universe, and claim that our best models are based on a perfectly uniform Universe, while the actual Universe is very inhomogeneous. Yet these claims often forget one very, very important point: we know exactly how inhomogeneous the Universe is today, and those effects have been quantified. BY ME.
Dark energy is no illusion, and here's the science to prove it!