What is the use of error notification email?

What is the use of error notification email?

If any error occurred during various operations of the app, it sends error notification email. You can add your mail ID in error notification mail where you want to receive all the notifications.

Open the App > Click on Configuration > Go to App Settings
For notifications on multiple email, you can add multiple email addresses under App Settings 
Important: Don’t forget to separate them by commas otherwise they will not be considered.