A common request is the ability to automatically create an Opportunity Contact Role record based on the contact that is selected in a custom lookup field. A nonprofit use case is the specific contact who is the primary Solicitor of a gift, who is not a user in the instance. The organization would want this as both a parent record (lookup) as well as a contact role for proper soft credit accounting.
It would be ideal if a Process could be built to automatically create that record based on the ID in the contact lookup. It does not appear that the Opportunity Contact Role object is available to select in a Create Record action: