Been a while since I made this, but from what I remember: Viewing the IP that a particular guest post was posted from is useful, yes. But under that it was basically showing a list of IPs that the user with the ID of -1 had ever posted from.
So while the description was implying that the same person had posted from all those IPs, the IPs were actually from a wide range of different people who had guest posted at one time or another.
But yeah, not exactly a critical software update there
And outdated anyway by now.