According to our Cashu dev chat history, the first demo of an ecash payment via nostr seems to have been on Dec 26, 2022 https://video.nostr.build/6d373ceb148e7da53c4c4248d9096e4e008a8a2da0cc14c35c0aa0df57d26fd8.mp4
👀 nostr:note1fxw603vkdeqfh8ay9htupj774az3gncpuh8rfd74798xs3srmprq65mfq3