I thought the same thing. Perhaps this is just a test run to see how well his bot gets past the mods without the telltale sign of spam links. Also, if you can flood a site with enough posts and then update your signature with the spam links or just edit your saved list of posts then it would make it difficult on the mods to remove.
You think he's running a bot to amass forum cred? Do programmers that good have that kind of spare time?
This is all just speculation.
But I once wrote a command.com virus just to see if I could. I called it potato. It would rewrite command.com and call my own executable that was hidden. It created a shell of the command environment and would function as normal and would put "one potato C:\>" "two potato C:\>" and so on each time you entered a command (this was back in the late 80s). But other than copying itself, it didn't do anything else. I did write in an escape from it and it was pretty obvious. If you typed "more" when it said "seven potato C:\>" the program would end.
Anyway, programmers will write stuff just to see if they can.