The danger of technologies that promise a longer life is that they commodify what should be a spiritual conversation about what it means to want to live, and what it means to want to live longer. In principle, I see no reason to object to having a longer life. I'd like to see people in space. I would like my child to have more time to grow and love and learn. The danger of genetic choices such as this is that they cast parents in a more perilous role.
Parents already come to resent their children as they age.
I feel myself dying, even as my child grows and grows out of the society and needs that for me are most important. I'm not sure. Finally, I would be among those paying for extra years. But I am not so sure that such a choice should be mine in the first place. When I think about what it takes to help a child become a responsible, contented, socially useful adult, genes are only a minor consideration.