That's the thing that is the bottleneck preventing a major breakthrough. Once a delivery system is in place a lot of diseases such as cancer and HIV will be preventable. No, absolutely not. Having the full genome available on hard drive and searchable just facilitates research. We are in no position to change the genetic information at a single locus in a human cell.
Gene delivery is still the limiting factor.
You can do things in a laboratory, but when it comes to people the situation is very complicated and cells are specialized and complicated by the immune system. If we succeed in doing that, yes, you could start changing the human genetic makeup at will. Billions are being spent on gene delivery and so far the most advanced is viral so that the virus carries the genetic information to a specific cell. Once the genetic information is delivered you can't control where it will end up. Also, the virus itself causes an immune response which eliminates the cells.