My interpretation: Illusion of information relates to adequacy when evaluating if you have all the necessary information, leading to potential misunderstandings or misinformed decisions because of unseen gaps in knowledge.

The Dunning-Kruger effect is about misjudging your own abilities, leading to overconfidence in tasks or self-rated knowledge of domains.

Both tries to explain why people make mistakes, but one through the lens of cognition and information processing, the other to through arrogance and level of domain expertise.

If these concepts are useful is another matter.