from Fundamental Rules & Concepts:
At its core, Saga is a storytelling game. Adventures using this system are run by a Narrator or Storyteller, who dictates the path the story takes and obstacles the player-characters (PCs) face. Players narrate their characters' actions, just as Storytellers narrate the actions of Non-player Characters (NPCs). Both Players and Narrators will occasionally roll dice to determine the outcome of conflicts between two or more forces.
Like so many other systems, Saga uses dice rolling as a mechanic to resolve conflicts. This is true of Conflicts Between Characters, such as one character firing a gun at another and the second attempting to dodge, or two characters arm wrestling. It is also true of Conflicts With Environment or Objects, as when a character attempts to pick a lock, leap across a chasm, or walk across a tightrope. Conflicts of both kinds are resolved as described in the section entitled Conflict Resolution.
Random attribute generation is only one of the three options available, along with "free choice" and "stat cap".