The loading phase frankly was designed for studies. Studies are often short-term, say 6 weeks. You've got to get everyone's creatine supplies "loaded up" quickly in an effort to make sure the bulk of the study is on folks with relatively comparable creatine stores. The easiest way to do this is to have everyone do a loading phase to reach max intramuscular creatine concentration. It is not for the benefit of the study participants; it's for the benefit of the study.

We humans not in studies are generally looking for a health benefit, not max intramuscular creatine concentration as fast as possible at the price of side effects. We are optimizing for something different than study authors. 5 g is fine.