In the United States, few people can get ahead in many fields without "educational" internships. In theory such "practical learning opportunities" can strengthen skills of students and others who participate. In practice, interns are exploited and often provide work that deserves wages without an accompanying educational experience. This is true of both post-graduate internships at companies and graduate internships in the fields of social work, business, medicine, and more.
Unpaid internships are not acceptable in a nation where the average college student accumulates thousands of dollars of debt. Even internships that are truly educational should pay their students, not the other way around.