The supplier profile questionnaire is automatically attached to any supplier record in Ariba SIPM and serves as the main profile for that supplier. The 'organization profile' comes from the suppliers' Ariba Network account which the supplier can update at any time and the SPQ is filled out by the suppliers' contacts upon onboarding and possibly once a year if set up to refresh as a task.
Surveys are used to measure performance or risk and are part of 'performance projects.' The vast majority of questions are answered by other users of the system (supplier managers, commodity managers, procurement leads, supply chain etc) about that suppliers' risk / performance and in some cases questions may be answered by the supplier directly - it is fully configurable. It is the survey document which can populate the scorecard with grades based on participant responses. In this case, you set the KPI's first, attach them to the survey, then create the scorecard linking back to the survey. This process is covered in the help guides.