Firstly, Guerrero never held a midcard title after he won the WWE championship. Triple H only held it during the time he was in the most powerful fucking stable, he held it for the sake of them having all the titles and playing second fiddle only to the greatest star in wrestling. And the fact that you even brought up Benoit, one of the most tragic and awkward careers is enough proof that Punk should never win that title. Benoit went from world champ to competing in midcard for the rest of his career (of course he helped a lot of upcomers, but Punk is too young and too valuable to make the crowd believe he is now in US title competition, it's wasteful, he's been treading long enough but the WWE has at least kept him in upper profile feuds with the likes of Rey and Show, so that was good. Look at it this way, Punk is equal to Sheamus, would you want to see Sheamus competing against Danielson for the US title? NO. That'd be fucking Blue).
I compared the two because they both helped each other propel themselves into the main event and Hardy was the most consistently over guy during that time period, just like Punk was one of the, if not the most over heel (can't remember). That title means shit, the equal cross brand belt is held by Dolph Ziggler. It's so painfully obvious that Vince and the creative hardly care about it, and that most/all of the time when you are an established star and actually propelled that far down you never come back, like Benoit.
Oh btw, Benoit's world title run was nowhere NEAR as sucessful as Punk's. What exactly did his reign do? It did nothing to get Triple H more over as a heel, he was later on just fed back to him and then Randy Orton, who it did nothing to get over as well since his face turn failed. Punk's allowed him to transition to the epic heel, that YOU and I both see today, as well as made Hardy the most over fucking face in the company by giving him his big win to run with and the perfect antagonist.