They wouldn't have been sparing her from anything except being born - the embryo that became their daughter always had those genes. The choice they actually faced was whether or not to discard that embryo in favour of any they might have created that did not have the gene sequence in question.
After the fact, that choice is expressed as: "would you rather not have had your child but had another one instead?" which in 99% of cases will attract a hot NO in response.
Further, it asks the affected parent if s/he would rather not have been born. And again the answer is obvious. Very few people even who suffer would rather never having been born.
So I don't think the decision was based solely on finances and I don't think anyone should be obliged to screen for hereditary conditions. There are plenty of things in my family history or DH's that I'd rather the DC didn't inherit, but it's a huge leap to say I'd have wanted the opportunity to screen them out.