Item 2 updated for vRA 7
vCO Endpoints are used by vCAC when vCAC needs to execute vCO workflows. These can be out of the box workflows such as the NSX workflows, or they can be workflows that you created and want vCAC to execute as part of a deployment state transitions such as during building machine, machine provisioned, machine destroyed or various other master workflow states. vCAC cannot execute these workflows without first having a vCO endpoint to which it can query and call to execute. vCAC can pass machine custom properties and other information through to vCO as part of the execution to parameterize the workflows.