yes, some genetic testing is useful. very little of it makes an actual impact on human health, compared to far larger contributions from other fields. It's just oversold.
Note: I have 25+ years experience in this field, I'm not just spewing out random beliefs.
You probably have much more knowledge than me then, but based on the reading I've done, we now basically know of certain genes that make people far more likely to get diseases like alzheimers or even to get a diagnosis of autism (genes which make the body unable to detoxify heavy metals) - it seems to me like that sort of information is probably instrumental in being able to fully understand and eventually cure or prevent these diseases, no?
Note: I have 25+ years experience in this field, I'm not just spewing out random beliefs.