I am one of the original authors of Kafka. Kafka will work very well as a log for event sourcing. It is fault-tolerant, scales to enormous data sizes, and has a built in partitioning model.
We use it for several use cases of this form at LinkedIn. For example our open source stream processing system, Apache Samza, comes with built-in support for event sourcing.
I think you don’t hear much about using Kafka for event sourcing primarily because the event sourcing terminology doesn’t seem to be very prevalent in the consumer web space where Kafka is most popular.
I have written a bit about this style of Kafka usage here.