See my other comment, but in short I essentially mean the true realization of "precision medicine" and gaining a greater understanding of how different genotypes result in disease, information which can be used guide treatment and to develop better treatments.
> That assumes there's someone out to get you specifically.
Not entirely true- the ability to reconstruct genotypes from environmental samples gets better all the time. I'd imagine that even with current technology, a sufficiently motivated organization could sample various locations to reconstruct the genomes of people who often visit there. With enough info, they could start building webs of genetic relation. From there, all they'd need is access to a database of samples from known individuals (which, as we can see, already exists), can chances are they could quickly deanonymize future samples. The only thing that could stop such mass collection is proper regulation.
> That's like saying there's no point in having 2FA or strong passwords, because the FSB, the FBI and Mossad can get in anyway.
Unlike your password, your DNA is unencrypted and gets spread everywhere.