There are two scientific theories for why that is currently. The first one is the simple fact of different brain processes. Visualizing while awake is a "top-down" process controlled by the cortex, while dreaming can involve more "bottom-up" processes organized by the brainstem. The second one is that aphantasia may not affect all parts of the brain equally.
Neat distinction. That tracks for me. I have two kinds of visualizing.
One is very deliberative, where I am using my mind like a big 4D interactive painting to plan and examine, and use visual thinking to explore subjects. Sort of like having a VR room in my head. This is where I spend much of my time professionally and personally, and information for me is very visually encoded, like a big mnemonic map. I use it as a tool to think about work projects, UI/UX design, or other visual tasks. If I am plotting a long trip I like haivng these in my head as a map.
The other form is when creating concept art , and is much more shamanic. I will go into an alpha state and enters a hypnogogic state where I am dreaming but also have some control over the dream, which I can "seed" with ideas and explore emergent patterns for art or visual design.
I was once working as a concept artist on a well-known game franchise , and in my office at work I'd turn down the lights and enter a dream where I was wandering though a fantastical environment for the game, looking for interesting patterns and subjects. After "dreaming out loud" I'd then jump up and sketch them. One time I forgot to turn off my office phone, it rang, and "poof" the most amazing dream was gone, never to return.
Aside from Neville Goddardian New Thought , I actually don't rely too much on this faculty in Goetia much. It's too inner "projecty" and just feels like work. Sometimes I will do it just to keep my brain occupied while saying prayers and invocations, but I do try to keep my visionary qualites to a minimum. It is all to easy to get wrapped up in astral forms, I feel. The things I feel are important are BEHIND the forms. And will use those forms to communicate.
I don't want to share too many of my visions, becasue I feel they are for me. But some time I will be "taken" to a place I named after a Clive Barker story, The Gyre, a place where I float above a roiling field of dark clouds below and a transcendent ocean of yellow-golden light above. The balance of Above and Below. Does it really exist? Not literally. But yet somewhere it does. The Crossroads of the Worlds.
The first time I was there I was like , "Pfft, how original. Feet in the hells, and head in the heavens, eh, subconscious?" ". In my view this is how my very visual central nervous system is interpreting some experience , whatever it is. I feel is a real place, probably exists in other dreams in other forms, but until I get someting more tangible out of it , if i don't get a feeling in my body afterwards, it's more like "Cool, story, bro."
If this was 20th century magic they'd make a pathworking for folks and sell it. I usually like, 'just use the grims.' Your subconious wil interpret the Sginal from Beyond in your own language. No need to use mine.
So wher to place it all. Visual + kinesthic feeling + results magic is where I place maximum "truth" for me. But feeling is probably more imprtant most of the time. Visions that's just a day at the office or regular life for me. I like it whe magic hits me and I feel it. Visions are just a bonus.