No, your right, I realized I misread the post, sorry about that.
Though, in the spirit of trying to keep a talk going since you like the topic, it could be possible that after defeating yourself from the future, you could come to the realization that in the future, something will happen that will cause you to be so desperate for money that you consider robbing yourself in the past to be a viable option, thus you go in to training to get better. When the time comes that for some reason you think robbing yourself is the best option, you have trained yourself to be better at fighting. Fully confident that your training has prepared you, you go back, fully bearded, ready to go, only to unfortunately get defeated by your past self.
I know that is a stretch, but it is possible.
Then again, I guess that depends on how you view defeating your future self in the first place. I gave it a shot.