Armor augments are the deciding factor between life and death. As skilled as a warrior may be, no one is invincible.
Choosing how to augment your armor, in addition to what new effects and perks this augment will give is what gives each player their own style and flair. Each new augment enhances the armor you already have, both visually and through its ability to protect the wearer. The visual component of each augment is dependent on which perks and stats you as the player will allocate into, to truly specialize your class to fit your unique fighting style.
Armor augments are among the prizes earned from exploration of the world, revealed through solving puzzles, killing powerful enemies, and finding materials with which the player can physically forge the augments onto their armor.