I suspect even if Google knew that the application would be rejected that they still would have developed it to start a PR coup to knock the iPhone off of its pedestal. I don't think Google really cares all that much about Google Voice in isolation -- it's of limited strategic value by itself. But if you see it as part of their overall mobile strategy of commoditizing the smart phone market (which Google Voice also helps), and if you look at how important it is for Apple that that not happen, I think the conflict of interest has more teeth.