The thing is it's not much data in absolute terms, but it's not going to change for over human timescales and tells you something about your entire family, going back generations in the past and many in the future. On the other hand, look at GWAS studies, if you have many people and know if they get a disease or not, you can narrow down exactly what parts of the genome are implicated in the disease, and start designing drugs for it. It's hard work and doesn't always work, but it allows us to go from high level disease phenotype -> exact mechanistic problems