Look at Zeebe[1] for example.

If you declare the business process you want to support - either in code or in BPMN, you're automatically mapping out the events that are relevant to the business.

Having a system that takes care of executing this, and tying the pieces of this workflow together is one example where ES can shine IMHO.

[1]https://docs.camunda.io/docs/product-manuals/zeebe/technical...