Let's suppose a website that sends (useful) mails from a "noreply address". Nobody read messages from this mailbox because it is just to notify (useful) information.
At this time, if someone, sends an email to noreply the silence is the answer.
But, here, they are a person with a great idea: set an autoanswer on noreply mailbox to reply people with a message "this is a noreply address, no body read this message, thanks".
In my opinion this is a kind of oxymoron, an autoreply on a non-reply mailbox. But, may be, this is a bad pattern in other effects that I can't see at this moment or may be this is a good solution to let know people don't wait for a reply.
Notice: ( Edited due Pectoralis Major's answer )
Body eMail contains a link to https webapp. User can be in touch with service through the webApp easily. eMail is not a secure channel and messages can contain sensitive data.