Quantum computers are already here in a limited form, and fully functional versions are on the way. They will be as transformative for mankind as were the mainframe computers, personal computers, and smartphones that we all use. As do all advancing technologies, they will also create new nightmares. The most worrisome development will be in cryptography.
Scientists have assigned the role of Mister Answer to science, the source of knowledge on every subject. This is peculiar because science does not accept a complete body of knowledge at any one time as final, therefore no answer can be final. This is how science progresses. Scientists, though, often forget that.
Greater comfort, I think, is to be found in the realization that infinity is as problematic for science as it is for religion. Much as an infinitely perfect God leads to logical clashes with reality, an infinite multiverse bedevils attempts to apply tools such as probabilities to our understanding of the world.