Certificate of Conformance and/or Analysis – which to use – myASQ

Hello, I am wondering if folks have insight around Certificates of Conformance – maybe specifically why a customer would need a CoC when a Certificate of Analysis (CoA) is already provided? I deal almost exclusively with CoAs at my organization but occasionally have requests to provide a CoC, usually in addition to the CoA already provided. The system we use can generate one or the other systematically so these occasional requests have to be addressed manually. My only experience with CoC is that they are more often requested for border crossing/maritime shipments so I don’t know if this just happens to be country specific (the country(s) a product travels through not necessarily the end destination)?