Not a biologist, but I'd imagine that's because we currently can answer "is this DNA likely the same as that other DNA" with some degree of reliability, but any

Not a biologist, but I'd imagine that's because we currently can answer "is this DNA likely the same as that other DNA" with some degree of reliability, but anything more (except for some very specific diseases) is still not quite here yet. I'd also imagine all this is changing very quickly. Happy to be corrected by someone with actual knowledge of course.