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.

This sounds intense... I'm a small female and I recently started at 5g a day and now I've dropped down to 2g a day because even at just 5g I was getting signs of dehydration, despite tripling my water intake. It does seem to make a difference in my physical performance so I'm overall happy with it.

Also the NIH fact sheet for creatine specifically recommends against higher starting doses.

Per day being a key part of that. 30g at once is going to give a good chunk of people pretty severe cramping or a trip to the bathroom.