for the rest of the universe, getting zapped by Darkseid means you're done for. For Batman, very conveniently, it means being sent back in time, in an universe where time travel is like... foot travel, really? That's ending well in my book!!!
That doesn't mean that it would end that way every time. The Omega Beams essentially do whatever Darkseid wants, and if Batsy were to get zapped again, he could very easily be killed or thrown into a hellish alternate dimension from which there is no escape. No matter how you cut it, Bats got lucky, and only once.
That wasn't exactly my point. I meant to underline that the only time in all of comics history, in disregard of all previous examples, that the omega beams don't obliterate someone, it has to be Batman. I share nebezial's opinion on this and refer you to nebezial.deviantart.com/art/be….