It's exciting in the sense that you can apply all these open-source projects to create a very slick lightweight relational database that can replicate changes globally across unlimited instances by using a Kafka topic as the WAL log.

Don't actually use this in production. Use a real database that does what you want, and use the native replication features. If you need to replicate to heterogenous or alternative sources or just want a stream of all changes then you can use Kafka with any number of existing database connectors that automatically read and export changes.