In the last stories involving DC Universe, some events has made me think the Injustice's reality has an important role for the saving of the multiverse. And for that reason, Injustice Superman's has to be the winner of this conflict with Batman.

1º) The Dark Knights: The whole multiverse started to be in seriously danger when the Bat-Demon Barbathos recruited a team of alternative versions of Batman. All of them versions of Batman who have commited much horrible things that Injustice Superman ever did, and who were willing to kill anpther world to restore their own. This proves Batman is clearly the most dangerous villain who ever lived, and his twisted/sick mind can take to disaster. It was the Dark Knights who even caused the Source Wall to be broken to beging with. Injustice Superman, an experienced guy who has fought Batman's twisted plots for years, would be the perfect guy to stop them from destroying the Multiverse. And since he's a Superman who kills, he wouldn't doubt into killing them instantly. (Surely, we would enjoy killing the Batman Who Laughs the most).

2º) Doom War: Well, it seems the Legion of Doom is going to cause evil triumph over good in a upcoming war. This would eventually lead to the destruction of the Earth and the Multiverse. Batman turns into the main cause of this disaster, and practically everything is destroyed. So, to avoid the Multiverse to be destroyed, Injustice SUperma would be the perfect solution. With his Regime, he will force the world to accept salvation and the survival would be asured. You might called tyrany, but I call it survival.

So, that's why I believe the Injustice World has to continue, until Superman has become the absolute winner of this conflict with Batman. You might don't like it, but the scenario in clear. With Superman, we might be oppressed, but we'll survive and have a world. With Batman, everything goes to Hell and everyone dies.