When I first saw it in Ady’s original Revisited, I just imagined how thousands of Battle droids must’ve been left lying around after the Clone Wars. I wouldn’t be surprised if criminals reprogrammed them and sold them as security droids. This just happens to be one that met its fate on Tatooine. It must not have done a very good job of protecting its master.
But that’s another reason I like it. It sparked my imagination.