I think "visual hallucination" is something very different from the minds eye. The imagination is one source of visual experience, the eyes are another. A visual hallucination is when something goes wrong and the data from your eyes is contaminated or distorted in some way. In my case, my imagination can produce photo-realistic visual experiences which are strong enough to block out the data from my eyes. They don't mix, but I can supplant one for the other at will. If they did mix I think that would be a disorder and we'd be talking about something other than aphantasia and imagination.