One of the more interesting parts of 23andme, at least for me, was finding second and third cousins (likely) that I didn't know. Most of the actual medical tests are fairly non-predictive (1.5x increase in one study for something which is already rare?), but the ancestry part is something where having a lot of participants in a selectively-open database can be interesting.

I do really hope Halcyon (or another company) gets full sequencing costs down as low as they say they can. Then, sequencing becomes just a routine checkbox on blood tests.