The treatment is a 2-part process and when complete the surface is neutral and hygienic. No damage is caused to the tile during the process. Very simply the treatment creates microscopic mountains and valleys on the tile by re-arranging the existing glaze on the surface of the tile. By creating the mountains and valleys the surface allows for water dispersement and prevents the occurrence of hydroplaning. Another feature is that tiny cup holes occur on the surface and these act like suction cups when treading on the floor.
So you end up with a surface that disperses water and has a minute vacuum. (Basically the same principle as a good car tyre.) The advantages are many, the most obvious being safety and cost savings (versus ripping and replacing). The disadvantages are virtually nil.