For which use cases would you need a custom action?

A custom action is particularly essential for calling a web service because it allows for greater flexibility and integration capabilities within NetSuite's architecture. When you need to interact with external applications or services, creating a custom action enables you to establish a specific workflow that includes making HTTP requests to retrieve or send data to another system.

In contrast, updating user roles, generating reports, and displaying alerts typically rely on built-in functionalities and standard workflows provided by NetSuite. These actions can generally be accomplished through existing features without necessitating a custom action. Custom actions are most beneficial when there is a need to extend the standard capabilities, especially when integrating with third-party systems or performing tasks that require nuanced control beyond the typical NetSuite operations.