The stated purpose of the hearings is to find out what went wrong and see that it doesn't happen again.
It appears that the principal lessons the Reagan Administration learned from the Watergate hearings is:
Reduce the circle of people who know (excluding even the President).
Make no recordings of conversations.
Destroy all written evidence.
Refuse to testify until given immunity, then have "difficulty recalling" events when questioned.
Wrap the whole thing in the American flag and accuse the accusers of prompting the affair in the first place.