There was a payoff: It is part of Spock's journey. It is used to make Spock understand how Kirk saw him, how important Kirk thought he was.
So all that stuff about Spock being genuinely emotional about those closest to him in the last movie was all a lie? Didn't the last movie establish to both the audience AND Kirk that Spock does indeed have emotions and he does understand the concept of wanting to protect those closest to him? It sounds like you're praising these writers for purposefully forgetting important character moments for the sake of recycling them. But that's not surprising since ID recycles a lot of the last movie anyways.