Depends on the data - if you had genetic data they might run PGS and infer that even though you are healthy now, your genes might predispose you to something bad and deny insurance based on that. If you truly do not see dangers of health data access remember that they could genotype you even when you came just for ordinary bloodwork.
Isn't it more productive to regulate health insurance and make health a protected attribute of a person like disability etc?
Fortunately I live in a country where one cannot be denied insurance, but yeah I didnt think of these really, was a bit of a “typed before i really thought” moment maybe i should put the keyboard down ;).
It seems like an easy fix with legislation, at least outside the US, though. Mandatory insurance for all with reasonable banded rates, and maximum profit margins for insurers?