I think it would be cool to walk into a room painted entirely with this material. I bet it would be so disorienting that people would fall down and get vertigo. So weird.
There's an experience worse than blindness—it's the certainty that your vision is perfect and the horror that there's no world around you to see.
So all the visual spatial cues would be missing, despite being illuminated, like being in an infinite space. I could see how that might be disorienting and strange feeling.
Another time I was flying a radio-controlled glider at the beach on a foggy day. There was a big rock sticking up in the middle of the beach. I thought the glider was closer than the rock, but then suddenly it vanished from sight because it was actually farther away and went behind it. Another flight I thought I was about 20 feet off the ground and then it suddenly struck the sand and slid to a stop.
The one window is thoroughly covered using well fit light blocking material. During daylight there is a very small amount of light the gets in under a door. At night it is utterly black. You may wait as long as you wish for your eyes to adjust; you cannot see your hand in front of your face. Nothing. Activating a smart phone becomes painful.
https://www.culturehustleusa.com/products/black-v1-0-beta-th...
If you scroll down the linked page, there is a photo of a vantablack BMW taken with a flashlight and a cell phone, and it simply looks like a dull gray when some light is pointed at it:
https://jalopnik.com/bmw-flexed-on-us-with-its-amazing-paint...
It seems like common sense to me that if you're looking at a picture on the internet that is staged just so, it is trivial to get all the "black" pixels to be exactly zero, but that doesn't tell you much about the quality of the material or how it would look to a person.
During the first gulf war they gave us some jackets that absorbed the wavelengths the night-vision goggles could see so you'd just see a human shaped void which kind of stands out a lot more than a regular person -- not the best of plans.
As will rapidly moving copper, or rapidly moving depleted uranium, or even a rapidly moving wooden stick with a stone point on it. :)
Peaceful or nightmarish?
Darkness is probably more disorienting, but also more familiar.
There's a single bare lightbulb suspended out of reach in the void. The walls feel like ScotchBrite though you can't see them. You aren't wearing any clothes. The room begins to rotate slowly as if it were a large tumble drier, rolling you off your feet. The walls gradually turn red.
Peaceful or nightmarish?