Possible use cases

Logging adapter

Magento is emitting logs of different levels with the default target of text files. It may be changed to the dispatching events, containing log records and their metadata, allowing Event Bus Rules to perform sorting and take appropriate actions in real time. Higher priority logs may be stored into a specific storage and have a system of alerts setup.

Notifications of business events

Order entity in Magento terms has multiple possible statuses and business events associated. It may be created, invoiced, shipped, completed, cancelled, etc. It's possible to take advantage of the Event Bus Rules and build a notification channel for merchant sales team, posting notifications of the selected events to a messenger, for example Slack. This kind of integration may also require a lambda function to process and forward records.