Perhaps the insurance company will not give you an insurance at all if you are deemed a high enough genetic risk. Perhaps, while the main disease works its way, you will not be covered for the side effects (like pneumonia) either, as you have no insurance.
This might or might not be an issue now (regardless of the place of residence), but laws can always be changed. And societies can always develop to be more totalitarist, even up to extremes, and it is not like the collected data just vanishes when things start to slide. (Case in point: IBM's Hollerith machines and population records)
I was very curious about 23andme and really wanted to try it. After some due diligence I concluded it is not worth it because of privacy and other implications going forward. It is not what they do today, since they don't hide the obvious sharing and datamining, so if one joins them it is through informed consent. My concern was rather what kind of systems and policies they enable eventually in the future, after the information gets sold/shared enough times to anyone who can pay enough. At this point there is no control anymore in how (and by whom) the data gets used.