> To see something in your “mind’s eye” has nothing to do with physical vision, yet the afterimage works by exhausting some of the eye’s physical cones. It’s a confusing non sequitur and totally unrelated to the subject at hand.

Which they go to the correct length to explain in the link associated with that demonstration. I found that exercise quite apt. They aren't saying "This is what non-aphants see" but rather "This is an approximation of what someone who can see images in their mind sees using a separate process so that you get an idea".

For me, the afterimage effect really DOES look similar to aspects of my own internal image perception (colors that are sort of there, but not quite; hazy quality; transparency).