There's really no call to espouse another reason while old bluestone sidewalks are so much more aesthetically pleasing than concrete sidewalks. We all know it is. But here's one anyway.
Above, is a stretch of bluestone sidewalk in the rain. Notice how it shimmers, how it reflects the sky and the shapes of the things around it?
And here is a piece of concrete sidewalk in the rain. Dead, blank, mute. It has no communication with the surrounding block. Just some square slabs.