In modern web world, URL is not just a link of a HTML page, it could be something else, for example, a web service.
Consuming a web service and data is returned, this is nothing to do with HTML.
I think the cloud authentication(SAML and SSO) is more designed for browser user, it's not convenient for consuming web service in development.
When consuming a web service, I don't want HTML or redirecting button in the response.
So from design view, page and service are both cloud resource, but they should be treated differently when being requested.