Is supplementing with creatine harmful?

Creatine is not protein. But generally protein supplements are not addictive. It is like eating food, except protein powders are generally more convenient and contains higher quality protein. The only "addiction" that might occur would be psychological. But if you understand the concepts for nutrition, you would understand that you don't need to take protein powder to gain muscles. Its is a easier and quicker fix to help you achieve your diet goals.