We all know that Cena would have been front and center and put Miz over in this little feud if creative had booked it that way, but other then that, why did this feud even happen? Did Miz piss somone off in WWE management or booking? He comes out for weeks trash talking Cena, the Big Show gets involved for a while making it a three for all, and then Cena and Miz have two matches, one at a Pay Per View and one at Raw, and Miz gets buried twice! He barely even got to use any decent offense in either match. Now I am not a huge Miz supporter, but this feud almost seems like someone in WWE changed their minds about the outcome midway through it! All the hype, and no reward,IMO. This feud didnt even help out Cena, as all he did was beat a weak mid-carder, main event wanna be.
I'm tired. So I'm not going to launch into this post. I will, however, answer the question of the thread.
There WAS a point to Miz/Cena. A big one, incidentally. No one would ever believe Miz could beat Cena. No one. Not ever. So, in order for Miz to be a main-event heel (which they want, considering they really only have Orton and Big Show up there) he needed a feud that could build him that high. Who better to feud with than Cena?
They had Miz be himself, a cocky heel. The first match they had, Cena owned Miz. That's reasonable. Miz was a tag-team champion at best, going against a former World Champion Cena who had been rediculed by Miz for how many weeks? Cena was pissed. He trounced Miz. It's what happens.
Then, they had a rematch the next Raw. The entire match's story was Miz learning from that past Sunday, and giving Cena a run for his money. It hinged on Cena selling incredibly well, a la his match with Swagger. Cena delivered, and made Miz seem a credible threat. If you want to see another example, see Orton's match on Raw against Dibiase. Incredible recreation of what Cena did for the Miz and Swagger. Miz is all the better for having both matches with Cena, even though he lost both times. Miz got a mega push on that Monday Night Raw alone.
So. That re-telling of the feud was all for one point. The point of the feud was to sell Miz as a legit threat to Cena, and by association, the main-event. Cena and Miz pulled it off.
On top of that, if Cena wins the championship at NoC, Miz has an instant window into a main-event feud. "I'm 7-2!" See? Creative isn't completely clueless.