The phrase "illusory nature" means that something appears to be real or true, but is actually false or deceptive. It refers to something that gives the illusion or impression of being genuine, but in reality, it is not. Full definition
«It is as though he [Joan Miro] had decided to condense all that he loves most — women, the night, stars, birds, dewdrops at dawn, into small paintings, while emphasizing the precarious illusory nature of our existence.» (galleryintell.com)
Hear hear, especially that bit about the illusory nature of some of these ICO terms, or even some non-ICO» ed coins I could mention. (prestonbyrne.com)
I experienced a blessed clarity, freedom and relief, and a stunning sense of the illusory nature of the life I'd left behind. (religion-online.org)