Arbitrary REST request from Kinetic app?

For some reason, I was under the impression that we would be able to easily make arbitrary REST calls to other services in the Kinetic App Studio. I’m happy that functions are significantly easier to call, but am confused by the the “rest” action under Rest Services in the event designer. It seems that you’re forced to choose a Service, Operation and other Epicor related settings. How does this differ from the the “rest-erp” action?