I now (in the past, I thought differently) think it is a major mistake to use the "all that really exists..." phrasing as Wilson does in this article. That is the method by which Religionists and Academics fool people into thinking that Epicurus is not worthwhile because their lives are only illusions -- "not really existing."
Sure the atoms and void are what have ETERNAL and UNCHANGING existence, but the bodies that are formed from atoms and void during our lifetimes are very real to us, and those bodies are every bit as "real" to us the atoms themselves. In fact, the bodies that we see and otherwise sense are in our own experience ALL that is really real to us!
"Epicurus, by contrast, was a materialist. All that really existed, he declared, were indestructible atoms – tiny mobile particles, invisible to the naked eye, with various shapes and sizes, but devoid of colour, odour, flavour and sound, and separated by void space."