What does Corrupting pit's do? do i need to do it for the corruption route? or to to get corrupted further?
It's for decreasing your overall corruption points.
Think of corruption points like water in a cup. If the cup overflows, you Game Over.
So you 'spend' them on corrupting your pips and nodes, to lower the level in your 'cup' so you can take on more corruption safely.
That makes since, Thank you!