although school may not teach you how to be a YouTuber, it does embed it you a core educational curriculum, helping you to be a well-rounded person.
also, learning things is an essential part of growing, physically, mentally, and socially. the school environment helps you learn social interaction, and what is acceptable behavior. it is important to learn that you cannot just do whatever you want, and school helps you to learn why, but teaching you the history of those who've tried to.
additionally, it is essential that you know that you never truly stop learning. even as a YouTuber, if you just do the same thing constantly, people will get bored. school helps you to learn how to do research more effectively. school does not teach you EVERYTHING you need to know, so it's vital to know HOW to obtain information on your own, and be able to continue your educational growth long after you graduate.
i learned most of my tech knowledge AFTER school, but the core of it was developed in school.