Barry needed to do the impossible. He needed to catch that moving phantom. In order to do that he had to clear his head so that he could act quickly and spontaneously, which he did. That's what it was all about. He became a true speedster instead of just an accident or something that resulted from a formula. He's really the Flash now, better than ever.
The Phantom wasn't real. The Speed Force prophets made it, and when they decided that Barry had finished their bizarre, stupid therapy session, he caught it. Barry has always been a true speedster. He's presumably the first speedster on his Earth, its impossible to be born a speedster so he's as legitimate a speedster as you can get. He's also no more faster coming out then he was going in, he's no better or worse for the experience. Well, except he can look at a tombstone now, but that really has nothing to do with anything.