I’d totally agree that the operating costs (speaking eng time, which is more expensive than machines) of Kafka+ZK alone is quite high.

If a company is not already using Kafka, they wouldn’t want to maintain it “just” to have a self hosted APM system.

If I could make a recommendation to the developers of this system, it would be to focus on the interface with the streaming platform, before the implementation of using Kafka to support that interface.

Ideally, one should be able to plug in and out the queueing system of preference.

This will help adoption, and avoid coupling the success of your project to the implementation and success of Kafka.