My theory is that looking at reflected light feels more natural than looking at generated light!
Our eyes are conditioned by evolution to see everything as reflected sunlight. It's just not quite right when what we're looking at is generating millions of points of light.
I love your theory,
@Matheo and the comments above.
@Matheo, I think you are correct as I have always felt this is a big part of the reason that makes a projected image so appealing. I do not speak from a scientific background and know not many factual details but I will say the following.
I often note the time when I tried going back to TVs circa 2016 and I still hated them. For me, it is also something about the image being trapped behind glass and something solid and tangible. It is more artificial feeling and looking. The projected image is, as you poignantly highlighted, light projected, onto a solid surface - from a single source, I assume? Thus, it looks and feels more natural for many reasons I do not know. Perhaps though, one is the way film grain is so beautifully exposed from projected light. And thus, perhaps a projected image closer in essence to it's source? Light. Perhaps, time is a factor, too? The distance at which light has to travel to the surface? Or perhaps, not? Since, I guess, from images online, that ultra short throw projectors still maintain the essential beauty of a regular throw projected image.
And as others have noted above, for me it is the size of the image; the sheer scale achievable with a projected image. And I will always take a weaker image that is larger (from a projector), over a smaller one that is stronger (from a TV). Also, the ability to fill one's peripheral vision, which is said to be unlimited on the horizontal plane, seems to me like maximising the potential of viewing images from a projector, compared to on a TV screen. You often see gamers achieving this by joining multiple monitors. One often has far more flexibility with a projected image too, being able to reduce or enlarge the size of it or place it in a specific place or on a specific surface.
Sound is also a major counterpart of most moving images, notably film, and what better way to view a film than on a massive projection, where the scale and majesty of sound, especially in a capable surround sound setup, matches the action on screen. Most of us will recall our fondest memories of image/ film from the cinema. We all know the deep-seated connection and sense of awe and wonder experienced and shared on the big screen at the cinema, and projection allows us to achieve this in our homes. To me, projection is a spectacle of the highest form, or in it's purest form.
My first experience of home projection was watching Escape from New York projected onto a bedroom wall at a friends house. It might have been a 4:3 projector. The feeling and memory stayed with me for a while before I purchased my first ever projector, a 720p Optoma. For me, the feeling and memory of a projected image is always a warmer one with more depth and detail both figuratively and literally speaking; in the experience, the feeling and the image, as it was in my above pivotal experience of Escape from New York. Or, I remember very vividly, not so long ago, the warm, orange candle light and flames burning in the lowly lit cabin, in the opening dinner scene of The Last of the Mohicans. It invokes an intimacy and feeling of warmth that connects me to the moment , the film and the characters on screen, more than a non-projected image would. So, there is an added depth I feel that is gained from a projected image. Part of this depth is the added detail gained, especially from 4K images, a large projected 4K image is far more spectacular to me in it's detail alone, over that of a smaller 4K screen. I am not sure how accurate they are, but you often see charts and measures and guides that specify the size at which 4K is optimal. I always felt it is from around the 100" when 4K starts to really shine. And I do not know of a 100" TV that exists, or if so, is affordable.
At it's core, for me, I guess then, that the nature of light has inherent beauty, and thus an image being formed directly from one source is immediately more appealing and astounding, compared to an image from a screen. But I regard all of the above components of light, form, depth, scale, flexibility and a projected image's marriage to sound, to add up to make it something so very appealing.
I love projectors.