Humans and chimps are extremely similar in terms of DNA sequence, over 99% identical for coding regions of genes, yet they are dramatically different when those genes act due to differences in expression patterns. Simply having genes does not make most of the difference. In the same way, just knowing the contents of a genome does not give the power to alter organisms, as in curing genetically-based diseases. One has to be able to also specifically alter gene expression to do that.
Work Step by Step
When large changes are needed which are genetically controlled, two things are possible: 1) change which genes are there (possible to a limited degree for up to a few genes at a time) and 2) change gene expression patterns (even trickier). Fixing genetic diseases could involve both 1) and 2), but this has proved to be very difficult at best.