The examples they show have little captions that say "best of #", like "best of 8" or "best of 4". Hopefully that truly represents the odds of generating the level of quality shown.
I don't believe it when Microsoft announces it, but when two separate trustworthy-looking hn accounts tell me something is crazy good that seems like valuable information to me.
I got the occasional A/B test with a new image generator while playing with Dall-E during a one month test of Plus. It was always clear which one was the new model because every aspect was so much better. I assume that model and the model they announced are the same.
I'm not saying that it's not true, it's just "wait and see" before you take their word as gold.
I think MS's claim on their quantum computing breakthrough is the latest form of this.