I really like the idea of having a 'pre-defined' set of edges where sharp creases are preserved despite the overall smoothing of the entire geometry. By having weights defined in advance along these edges, we can ensure that no subdivision would cause smoothing across the edge while still smooth over subdivisions anywhere else including the creases' immediate neighbors.
I agree, with the addition of sharp creases it opens the possibility of upsampling meshes that need to have a hard surface look, instead of smoothing the entire mesh over so details are lost. I think a good example of this would be if you had a mesh that is supposed to represent a metal surface with metal etchings. If this mesh was subdivided, the etchings would be rounded and soft, ruining the appearance of the hard metal etching.
When I was taking a 3D modeling decal, the instructor told me that I could add more edge loops right next to the crease so that it remains sharp in the smoothed mesh. I think in practice, it might be hard to keep track of these selected edges so 3D modeler tend to take a more practical workaround.