The energy of an impact or abrasion to your concrete will likely be concentrated on a small piece of your concrete, which is already, by it's nature, brittle.
In order to diffuse those forces you want to distribute them throughout the concrete so that the whole piece is sharing the load. Creating internal network of tensile strength does that and also minimizes the size and amount of cracks, chips, and pops that still can occur. Uniform bleeding helps with abrasion.
These fibers are proven to diffuse the damage of impact and abrasion throughout the whole of the concrete.