I worked on this while I was at LI and I think the major selling point back then was Replayability of messages but it was something similar to what you would get with Pub/Sub. We could also have multiple clients listening and processing same messages for their own purposes so you could use the same queue and have different clients process them as they wanted.

Its the ability to replay messages at later notice when needed.

At least this was the reason we decided to use Kafka instead of simple queues.

It was useful when we built new consumer types for the same data we already processed or we knew we gonna have later but cant build now due to prorities.