The Log Viewer is designed to view historical log files that have been saved either manually or from the router/viewer configuration. If you are streaming a high number of messages through the system, you will no doubt collect a lot of log files; they may need to be viewed. I wrote an enterprise-grade microservice system for a client that used ReflectInsight at the center of its system and streamed messages to and through a RabbitMQ system.
On average, we streamed roughly 1 million messages a day (it is still used in production); when problems arose, the Log Viewer's historical logging capabilities were invaluable.