In the GxP world, test execution reports for any validation exercise contain most important artifacts that serve as evidence. Audit trail of 'who did what? at what time?' are captured in the form of actions and results with time stamps, and most frequently with screenshots. In most test automation frameworks that are utilized in validation, a major gap is the presentation of this evidence that can meet the scrutiny of any inspector.
If you have n number of paths from point A to point B, which is the case in most software applications, then a traditional text based report is inadequate. "A picture is worth a thousand words" perfectly holds good here as well. A test sequence diagram for each execution can tell the story better that a thousand words.
In manual tests, it is almost impossible to test all possible transition paths in an application. However, much higher coverage can be achieved utilizing test automation frameworks (like model based testing). Here again, the main drawback with most test automation frameworks is that the evidence for such coverage is not available. A coverage graph simply solves this dilemma.