They have greater depth, variety, texture, and shadow than conventional three-tab shingles. That said, I wish I could afford wood shingles or a standing-seam metal roof. Drywall has evolved from being a poor imitation of plaster to a different tactile experience in its own right. Good drywall is perfectly planar and smooth. That smoothness can appeal to the perfectionist in us.
Plaster is a different experience.
It's modulated and textured and acoustically very different. Personally I like plaster better, but I also get a little rush when I step back and look at absolutely flat and perfect drywall. I think blueboard with plaster skim is the worst of both worlds. Expensive, yet inexpressive. Vinyl siding fails at all aesthetic levels.