It was a well-thought-out plan, with Amon acting as the villain for him. Faceless made it so that he could not be confirmed to be Ashcroft, at least not truly, which helped Damon. If he showed up and verified that this was Ashcroft and publicly took credit for defeating him again, this would make him the hero of the people who had been brainwashed and conditioned by the temple to view Ashcroft as a great evil.
Which meant the hero who defeated him was effectively untouchable, even by the temple, at least publicly.
With this move, the temple could not harm him in the name of justice or righteousness, because he was justice. He was righteousness.
