It can be used as a queue but the bigger benefit is for streaming use cases. One of the key differences, among others, is that streaming assumes somewhat faster consumers as opposed to queueing. There's also the pub-sub use-case which is generally considered separate from that of a queue (considered a point to point transport).
That is more descriptive, but it still sounds like queue functionality. Streaming processing is just a queue that gets emptied quickly and pub-sub is just a set of queues.
Kafka doesn't generally get emptied quickly, but rather retains messages for a configured time/size. Because of this, consumers can choose to replay previously consumed messages, if they wish to do so.
