its a cool service, you basically make a link that you send to the person via nostr dm, and can set parameters like link expires after (x) views or 24 hours. so they can open the link, get ur shipping info, and not leave a permanent trail in a nostr DM of sensitive info.

SimpleX cam be used to do the same. you can make throwaway nyms in simpleX for such things like transaction info...but the seller needs to have simpleX too.