For Automate Tasks (Bulk Actions, Rules and Scheduling) you can select different ways to be notified once a task fires. Below we clarify each notification functionality with use cases:
Email For Approval - (Rules Only)
Use case - I want to be involved and manually intervene. Send me an email and I will approve the changes
Run & Email Results
Use case - Automatically run the task that I have scheduled/planned, and email me the results. I want to be informed.
Run & Email Errors Only
Use case - Automatically run the task that I have scheduled/planned, and email me only when errors have occurred.
No Notifications - (You will receive no notifications)
Use case - My inbox is already inundated with emails, I don't want to be notified.