Interesting point is the researchers also cut out a defective gene from the patients' skin cells when generating the stem cells (IPS). That's great news for people suffering from genetic diseases.
Another fun fact is that the Covid PCR tests... well, the PCR was intended for gene reading and multiplication, not for testing of a virus, according to the creator of PCR. That's the reason why its now discontinued by the CDC.
However, PCR is perfect in its original role of amplifying a gene sample, like in this paper, where its used to insert new genes and replace defective ones.