There is a very good explanation in the spring-data-redis documentation:

Due to its blocking nature, low-level subscription is not attractive, as it requires connection and thread management for every single listener. To alleviate this problem, Spring Data offers RedisMessageListenerContainer, which does all the heavy lifting. If you are familiar with EJB and JMS, you should find the concepts familiar, as it is designed to be as close as possible to the support in Spring Framework and its message-driven POJOs (MDPs).