I agree with the others.
This is just something I do when cutting out the original image. I cut slightly inside the line on the portion that will be covered with the patterned paper. I can't match exactly when adhering the patterned paper so cutting just inside on the bottom image keeps it from 'peeking' out around the patterned paper. Less frustration. I also use liquid glue when adhering the patterned paper because it give you time to adjust the top layer.
As the other person said, it is fun and takes your crafting to the next level.