It's not useless. We know enough about DNA to be able to make better humans, but people get real squickly real fast when you talk about that. It has stalled because of that. If we go in and just check the DNA for Downs or Parkinson's, we can't have a conversation on aborting the foetus without religious beliefs coming into play. Designer children aren't a thing, despite the ability to edit DNA to do specific things. Hair and eye color are easy enough to go in and edit for. Humanity has decided to opt out of doing that for now.