Hi @zschaffter,
From the PM: The setting is useful for customers who want to leverage the access token Auth0 receives to make their own calls to Google’s API. See the docs below for more info:
When Enable Users API is selected, indicates that you require the ability to make calls to the Google Directory API.
To retrieve additional user and group details beyond what Auth0 retrieves by default, you can use the access tokens returned from Google to call Google’s APIs. To securely access these tokens, follow the guidelines provided in Identity Provider Access Tokens.