The point is to admit you were wrong after the result is in.
The "Christian" aspect is the big talk I'm right the other side is wrong and I know what will happen aspect of these threads. It's boastful to pretend you know what the outcome will be but honesty about your mistakes means you should be prepared to admit you were wrong after the result is in.
The result will be known of course so saying there's no point in admitting you were wrong is like saying there's no point to admitting breaking a window - it's obvious the window is broken so why own up to it!