I find (1) to be the biggest snake oil of electrophoretic displays. The only case where it's remotely true is direct sunlight. In normal indoor lighting conditions they severely lack contrast/whiteness/blackness compared to a good screen or printed book, and are hugely dependent on proper lighting, for example your hand will give it shadow so you're practically forced to use the frontlight if your device has it (reMarkable doesn't), as it's almost impossible to light evenly and match the background otherwise. In other words, when reading indoors they have all downsides of paper with none of the upsides. It just doesn't work as "paper replacement", it's strictly inferior, and feels like a downgrade compared to modern active displays.
(3) is mostly matter of choice, and it's a feel of matte plastic, very far from actual paper.
(2) is the only reason I'm using it. It's thin (although not as thin as a piece of paper) and single-purpose, a physical product.
For what is worth, I am fully convinced that (1) (the paper-like visual feel) is completely true, not a snake-oil claim, even if it is just a perceptual placebo effect that is masking the ostensibly true nature you described. Placebo effects matter ;)
I guess I should also have added (4) this tablet is a lifestyle and fashion statement about having the disposable income to use it instead of an actual high-quality paper notebook.
(3) is mostly matter of choice, and it's a feel of matte plastic, very far from actual paper.
(2) is the only reason I'm using it. It's thin (although not as thin as a piece of paper) and single-purpose, a physical product.