I could for sure envision a situation where they use the encoded information. Let's say they find that the sample comes from a person who is predisposed to a heart condition and they already have a description putting him in the 40-50 age range. That's a pretty significant piece of information that can help narrow down a search or canvass, especially if there's any other meta data they can correlate to the crime.

Why would your example be unreasonable? Sounds like good police work.

Just that it is very unlikely that you could infer the clinical manifestation of a heart condition just from DNA alone...

No, I would not consider it unreasonable but a lot of people probably would. And I don't know enough about inferring future health conditions from DNA alone, but I meant it as an example for a future possibility. If anyone does know, exactly, what you can infer from DNA alone and how that would be extremely helpful.