Nakamura vs. Styles, one year later

With a year of hindsight, what was the point of Nakamura winning the Rumble and challenging Styles, just to lose to him for several months in a row? The whole feud feels pointless now and did nothing for either guy, other than to bury Nakamura in the midcard after it ended. Was there ever another endgame in mind? 

For that matter, why did AJ hold the title for so goddamn long after the feud ended?

I think the Jinder Mahal feud buried Nakamura much further than the AJ one.  By the time he got to AJ, Nak had been pretty exposed as not having anything left in the tank at that level.  From what I understand, AJ just really wanted to work a Wrestlemania match with Nakamura.  

As for why he held it for so long, who else are gonna put it on?  Daniel Bryan?  Good luck there.