Mr beast is realizing so many different new-new challenges in their youtube for their audience to earn something as a prize. For getting all the tractions legally it says, that the user should be 18 above for all these challenges. And it also says the audiences who take part in these challenges much be live in the United States preferably get a chance first, and the people use lived nearby in North Carolina because this is the place where all his content is filmed. So it became easy for Mr. beast to get people in from the nearby areas only.