Although everything you say is true, there is a very clear benefit of genetic testing that exists today. Many drug interactions have a strong genetic link. Take the common blood thinning drug warfarin for example. It's considered a medical best practice to prescribe this drug to patient's with a variety of heart problems (irregular heartbeat, history of heart attack, etc). A single dosage has wildly different effects on different patients however. The same dosage can cause fatal bleeding in one patient, while in another patient have no effect at all. Without genetics, the proper dosage is a crap shoot. With genetics, it's an exact science (as it should be).
And this is just one single example. Research is revealing more genetic-drug links all the time with relatively small sample sizes. Genetic sequencing may not cure every disease like we were promised ~10 years ago, but it is saving lives and is essential to the advancement of medicine.
And this is just one single example. Research is revealing more genetic-drug links all the time with relatively small sample sizes. Genetic sequencing may not cure every disease like we were promised ~10 years ago, but it is saving lives and is essential to the advancement of medicine.