OAuth supports different authorization grants.
• Authorization Code: used with server-side Applications
• Implicit: used with Mobile Apps or Web Applications (applications that run on the user’s device)
• Resource Owner Password Credentials: used with trusted Applications, such as those owned by the service itself
• Client Credentials: used with Applications API access
Integration Server Supports, Authorization Code/Implicit Grant which are more secured and best suited for Integration use cases.
Mediator Supports Client Credentials which is best suited for API use cases.
This manual process is required for only for getting the authorization confirmed, just like we provide authorization for third part apps using facebook/gmail accounts.
If you feel Client Credentials flow required in Integration Server as well, you can request a Brainstorm request.