A thorough knowledge of logic can be immensely helpful in our own reasoning, or when reasoning with others. But in addition to any pragmatic advantage, we have a moral obligation to be logical. Thinking rightly is not optional for the Christian. It is something God requires of us.
Why are Christians so reluctant to accept Genesis as written?
Those Christians who reject the biblical timescale or who embrace evolution often defend their position using the two-book fallacy.