Overview:
Users are blocked from using connected Apps (Navigate to: Setup --> Manage Apps --> Connected Apps). App usage is present. This can be verified by navigating to: Setup --> Manage Apps --> Connected Apps Oauth Usage.
Root Cause:
This is working as designed.
Solution:
Connected Apps can only be restricted for users using Profiles or Permission Sets. Connected Apps exhibit additional Oauth Usage if they are connected to an org, even if no users are given permissions to access the app.
Related Documentation:
N/A
Thank you