I mean if you're coming from the view of "does this change now have an effect on the whole organism" the answer would be yeah kinda. If you wanted to delete a gene and see what effect it had, if you only cha get one cell's genome, you'll never see an effect because it's just one cell out of millions/billions/trillions. On the other hand, if you inject the CRISPR stuff in a fertilized egg at the si gle cell stage, that cell will divide a bunch and then all the cells will have the deletion. Those are the two extremes, so you can target stem cells or remove blood cells and return them, but the idea is the same: you need to change enough of the correct cells to see an effect