As much as long-time fans take it as a given that Kirk and Spock are life-long friends, it's one thing to be told that and it's another thing to take a new audience back to the events where Kirk, Spock, and McCoy first became the united front they've always been on the show. Sure, audiences in the '60s weren't shown the beginning, either, but at this point, with such a daunting backlog of material, you have to give a new audience something, some definitive jumping-on point, and here, we get a story that isn't "just" an origin story, but is instead showing us what happens when the butterfly's wings reach hurricane force, when one incident snowballs into a universe that looks like the "Trek" we know, but where rules are totally different.