It would appear that the purpose of this setting is to cause the owner of the phone to miss incoming calls because they were in the bathroom and get annoyed at the caller for not calling whilst the caller gets annoyed at the callee for not answering. Instead of calling the option "One Beep," it should be called, "The Blood Thickens."
Sorry suitboyskin. I was hoping to talk with you last night, but my phone had other ideas. We have a bit to talk about too.
That's the first real asshole thing this phone has pulled. It shall be punished.