Why it is the default
Salt and pepper sits at the point where polished concrete stops being a gamble on the pour. Cutting through the paste into the fine sand gives an even, fine speckle that reads as one material across a large floor, and the light variation hides scuffing and traffic patterns far better than a smooth cream polish does. It also looks the same in ten years as it does on handover, because the finish is the slab. In commercial work this is what gets specified unless there is a reason to go elsewhere.
What it asks of the slab
A one to two millimetre cut across a whole floor only reads as uniform if the floor is reasonably flat to begin with. New commercial pours placed to a flatness specification are ideal. Older slabs, and residential slabs generally, need to be assessed honestly: we test-grind before quoting a level, and where the slab will not carry a consistent exposure we say so and recommend cream polish instead of taking the money and hoping.
Maintenance across a decade
Polished concrete has the lowest lifetime maintenance cost of anything we install. Daily care is a dust mop and a damp mop with a neutral cleaner. There is no recoat cycle, because there is no coating to wear through, and there is nothing to peel. Every five to ten years a burnish with a high-speed machine and a refreshed stain guard restores the sheen to as-installed. In a commercial building over twenty years the difference against a coated floor is substantial.