@starvinggamer: Except they didn't remove him from the baptism, they forced a new outcome from the baptism that never existed before. But the post credit scene seems to point to their actions not mattering at all, or perhaps there is another point in time that branches into that outcome no matter what
Why they didn't matter? The changes amount to erasing the Comstock branch. It doesn't rewrite history - it just removes that branch and allows the multiverse to sort things out. There won't be a Comstock to whom Booker can sell his daughter. The knowledge of everything that happened throughout the game dawns on the post-credits Booker. Same way as it did when he crossed into the martyr reality.
I wonder if this means that Booker will live happily with Annabelle. He did refuse the baptism, apparently, since he has a daughter. But since Comstock should be dead, will he therefore keep the child? What way is there out of his debt, then?
Also, it would be interesting to know what outcome Elizabeth's and Booker's effort would've had in the 2 other Chen Lin timelines, since they actually switched timelines before even knowing about the doors...