Healthcare credentials matter for many professions. Sometimes it's a matter of the school providing the right certification and membership training and sometimes a graduate must pass a professional exam. In some cases there is regular re-testing and mandatory skill upgrades.
When you think about the immense responsibility that a healthcare professional has, this makes a great deal of sense. Firstly, healthcare workers are in a position of trust. People are predisposed to believe people who work in medicine and health and see them as authority figures. Healthcare workers deal with people in a state of vulnerability, either those who don't have all their facilities or who are immobilized or in pain, or simply in the intimacy of a patient's home in the case of a nurse or a personal support worker. For these reasons, training from nursing through to pharmaceutical courses will also include an ethics component.
Teaching ethics isn't just about the simple concepts of right from wrong. It's also hard questions, for example when to notify patients about a diagnosis, who is privy to confidential patient information and what to do where the patient may have been involved in criminal activity or is a victim of abuse. Sometimes ethical questions may involve choices like whether or not to administer a treatment that could extend a patient's life but increase suffering. This is one of the reasons why the CRNE exam is constructed using input from working nurses and will have realistic case studies as examples.
Professional accreditation also makes sure that the healthcare worker has skills that are up to date. New medical research is occurring constantly. Treatments that were used in the past may be deemed ineffective or even actively harmful, while dosages and administration methods are being carefully refined. Pharmaceutical courses are expected to be current and be structured to train students the most modern practices. Courses taught several decades ago could hardly be expected to predict the plethora of drugs that are available today. In the past, antibiotics were constantly over prescribed, but modern know-how teaches us that this can be actively harmful to collective health or even the safety of the patient.
Another trend that encourages accreditation is increasing regulation and the legal due diligence to prevent litigation. Much like a restaurant will make sure it has qualified staff with a food safety certificate, medical facilities will hire staff that can prove they have a solid background. Professional organizations help compliance with regulations and care standards. For example, there is little oversight on who may call themselves a nurse, but a registered nurse, the kind that can work semi-autonomously in providing healthcare, must pass a national CRNE exam.