Depends on how much you will need to use these in your day to day responsibilities. I would say that if this is something that you will need to be using daily and requires deep understanding of then yes you should know the ins and outs of the graph algorithms.
All in all knowing and understanding Algorithms and computer science best practices from the ground up will improve your skills as a developer. Algorithmic design involves complex problem solving and application of logic to achieve a goal. Learning and understanding algorithms thus improve and adds to your analytical repertoire as a Software developer/programmer.