For what purpose should a fault connector be configured to send an email?

The purpose of configuring a fault connector to send an email is to alert when a flow fails. When a flow encounters an error, it is essential for administrators and relevant stakeholders to be made aware so that they can take appropriate action to diagnose and resolve the issue. Sending a notification via email ensures that those responsible are informed promptly, thereby enabling quicker resolution of any problems that may disrupt business processes.

The other options do not align with the primary function of a fault connector. Informing users about flow completion or notifying them of successful completion does not address error scenarios, and updating the admin about flow usage pertains to performance monitoring rather than error handling. Thus, the focus of the fault connector on failure alerts supports effective management and maintenance of flows within Salesforce.