pedestrian: The purpose of having rule 12 is for the end-game to be meaningful - or not awfully dragging. Image an end-game where there are only Kings on the board. Or both players having a King and a Bishop. Or King vs. King + Knight. For an OTB game, or a site that automatically determines draws, I wouldn't use rule 12, and just consider them draws (either directly, or using the 50-moves rule), but since this is BK, I think it's better to avoid positions that are draws, and require manual intervention.