Are you taking into account that your genome is inherited? If you have good knowledge of your ancestors back a few generations and their health you could probably make a pretty good guess whether or not there is some factor lurking in your genome that correlates with a disease severe enough to raise your rates.
This could make the potential savings worth the risk for some people.
(I wonder if a new kind of insurance would develop for the risk that disclosing your genome raises your rates?)
From a societal standpoint, we should work to make things like term life and disability insurance broadly available and relatively even priced, not rewards for good genes.
(there's lots of reasons, a big one is that they are often implicated in the standard of living that children will attain)
If you want to have other social programs that universally bolster standard of living, then it's fine to make insurance a stupid awful game for people to play.
This could make the potential savings worth the risk for some people.
(I wonder if a new kind of insurance would develop for the risk that disclosing your genome raises your rates?)