Better than tile; no grout.

It does not get cheaper, just because it is mounted vertically rather than horizontally. 15K just for some rock walls, is not going to be palatable for your standard middle class 30K hall bathroom. For a luxury home, sure. But it would not be wasted around a tub shower.

Any solid wall installation must be compared to alternatives with labor included. Tile may be cheaper, but takes longer, and labor is usually the largest budget component.

Thanks. Cost is not the major issue. I’m interested in grout line reduction