For questions regarding Aura.Action. An Aura.Action is a reference to an action in the framework.
Although Aura.Action works for passing an action handler to a child component, we recommend registering an event in the child component and firing the event in the child’s controller instead
- Don’t use $A.enqueueAction() in the child component to enqueue the action passed to the Aura.Action attribute.
For more on the component, refer to the Developer Documentation: