Friends of mine had a very, very early projector TV that had a large box about the size of a dishwasher housing a three-element projector that sat on the floor, with steel square-tubes that led to the wall, where an upright set of steel square-tubes had a curved parabolic screen mounted to them, that at the dead-center was exactly ninety degrees perpendicular to the projector. Even back then, the curve screen was not desirable, it was necessary in order to get the image to look right on a screen the better part of a hundred inches across the diagonal. The three projector elements were not perfectly in-parallax to each other when shining on a flat surface, but the curve of the screen allowed the image to be produced without significant parallax error on the colors.
I admit I was hooked on projectors from that point, but by the time I was able to get a projector for TV, office projectors that didn't need curved screens were readily available. I still have my first one actually, only 800x600 and a dim 300 lumens, but it has optical parallax correction and gets its image through a single LCD, so there are not problems with colors being out of alignment, and with the movable mirror for parallax and a manual zoom lens there's no problem with getting the image right within a certain bounds.
I just don't see any benefit in curved screens now, the content isn't filmed with them in mind, the content generally isn't even theatrically conceived to need a huge screen let alone a curved one, and the screens aren't so big relative to the rooms to where the curve offers a greater screen size than the room naturally could accommodate. So I agree, gimmick.