The main value Kafka provides to data pipelines is its ability to serve as a very large, reliable buffer between various stages in the pipeline.
bin/connect-distributed.sh config/connect-distributed.properties
The Debezium Project provides a collection of high-quality, open source, change capture connectors for a variety of databases.
Kafka can be looked at as a platform that can handle data integration (with Connect), application integration (with producers and consumers), and stream processing. Kafka could be a viable replacement for an ETL tool that only integrates data stores.