Messaging in an asynchronous inter-service communication style has the following benefits:

Message brokers provide an automatic retry mechanism. This means that if a service is not available, the message broker will send the message to that service again and retry.

The message broker also removes the coupling between services in inter-service communication. In our example, this means that the Book Service doesn't need to be available at the time the Order Service sends the message.

Messaging also provides flexible client-service interactions.