He remembers who he is at a really bad time.
("Oh my go - oh, man."
"But - Chuck, we haven't even started yet."
"I - I can't do this."
"What?"
"I - I can't. I... I respect you too much, Becky."
"What.")
So, yeah. Really bad timing for the omniscience to kick back in, self. Nice going there.
One thing he'll say, though, it does make the writing easier. No research required, no continuity-checking, just writing the Word. And some of the sentences don't even sound half-bad.
But all the same, it's still a little weird. How is he - alcohol-swilling, prostitute-visiting Chuck - supposed to be Him? It's a lot of pressure to put on a guy, all those expectations, hopes and dreams.
But that's probably why He became Chuck. To avoid all that.
Not that it helps him to avoid others.
("Hello?
"Oh, Dean.
"No, nothing new. Sorry.")
And once the story's over, he can't stick around. Dean and Sam have his number, and leaving a hint once or twice during the test is one thing, but after?
That's like cheating at life. He only does it on special occasions.
So he types up the last THE END, finishes off his last drink, and leaves Chuck behind.
They passed, so they get the reset they wanted.
He gets another fresh start.