Redis is not only for cache, but extra features such as persistence, publish and subscribe.

Difference between Redis PubSub vs RabbitMQ

Redis Pub Sub   RabbitMQ  
Used for simple publish and subscribe message Stable, reliable message and enterprise pub sub
Not store messages during failovers in listerner Store the messages for failover in listeners
No Support queues or point to point communication Support for point to point queue and pub sub