Need outbox for when emails don't send because of lack of network connectivity. After you hit send, there is no way of knowing if the email is slated to send once you regain connectivity.
Anonymous shared this idea
Ditto. Depending on settings for Draft folder, you can sometimes (but not always!) see problems there if you open the folder, but there's no obvious external indication otherwise. Just found an email I thought went out two hours ago lurking in my Draft folder (apparently because of network issue).