Answer: From the OP I deduce that the question is actually related to SDGs (Signed Directed Graphs). So here is my answer which addresses basic directed graphs then leads on to SDGs.
Directed graphs are widely utilized in fault-tree analysis in industrial systems. As you eliminate causes of a fault you follow the directed graph to explore other possibilities.
Directed graphs are utilized to prevent counterproductive revisiting of nodes which have been effectively eliminated. In fault diagnosis, often time to restoration of service is critical. In complex industrial systems there is always a parallel tree based on time which can lead to total system shutdown if the fault is not corrected within various time limitations. Going back and forth would be more likely to lead to total failure, which can cause restoration operations which are much more time-consuming (like draining tanks and pipelines in order to restart a refinery).
It is like trimming a tree branch - no need to go back to the trunk when you are trying to find a single twig.
SDGs have the additional property of giving guidance based on probabilities or thresholds in order to help make decisions as the tree is traversed.
Here is a link to a good book on the subject, called Fault Detection and Diagnosis in Industrial Systems (page 224), where it describes the benefits of SDG-based diagnosis: