I fear that if annihilationism is widely accepted by Christians, that will hinder the missionary enterprise. Many people have devoted their lives to bringing the gospel to the unsaved around the globe. Would they continue to do so if they really thought that the worst fate awaiting those who reject Jesus is final extinction? I seriously doubt it. Annihilationists can argue that the obliteration of the wicked is a terrible fate if measured against the bliss of the righteous. But when compared to suffering in hell forever, it is simply not that bad to cease to exist.