For some it is very useful. My great nephew's mom was adopted, so he had no clue what his heritage was, or who his extended family might be. Mom took one of the DNA tests and actually found her bio parents...and the answers to many medical questions and found out the Irish heritage. Now that we know, nephew truly can explain his red hair and very distinctive Irish looks. It also explains some of the medical issues.There’s nothing to be afraid of, so I don’t see why all the fear. I had questions, and I was shocked and surprised to find out what my past is. It’s fascinating .
The problem with those DNA tests is not what you find out, but who and what the DNA info is shared with. There is now a huge DNA base out there, and it's open to many governments. What THEY might do with it is the scary part. Bio-engineered and targeted weapons is just one of the possibilities.