I would argue that our interpretation of an ink blot is imagination rather than delusion. Human beings seem hardwired to interpret data, whether visual or otherwise. An ink blot (or cloud or tea leaves or whatever) might look like a butterfly to one of us, a demon to another, a little kid flying a kite to another. Those interpretations might or might not say anything definitive about the person describing it, but the ink blot is not an actual butterfly, or demon, or whatever ... it is an abstract form that is interpreted by a human being.
Personally, I think experiences of god are similar. A person has an experience. Some describe it as god, another as imagination, another as spirit, or mother earth, or our innermost self. To me, the experience is important. Our interpretation a little less so. And a label least of all. Why? Because "inner" experiences are very difficult to describe, and most labels are biased by our upbringing and current beliefs. Furthermore, choosing a label like god (or demon, angel, ghost, etc) all carry baggage. Ultimately, we often think we're communicating with each other, but we really aren't, because we rarely agree on the label's definition.