The goal of blasting you backlinks is that this approach will protect your money site from getting slapped by google. This way you get the benefit of strong links to your money site without the risks associated with large scrapebox blasts.
For example, if xyz.com was a site you cared about, then usually, blasting it would not be advised. In that instance, you would want to create some web 2.0 properties that linked to xyz.com and blast the hell out of them. That way, the links to xyz.com would be stronger and then the link from xyz.com to your money site would be even better. This is a broad generalization. However, this is probably the safest way to use scrapebox. Larger more established sites can take a bit more abuse, but then again you are also going to be increasing your risk levels.