I teach in a coding school and while there are tons of good contents out there they would hit a brick wall quite soon. We mentor them, we are there 8 hours a day + all day on slack to answer their questions. We run cognitive apprenticeship sessions (live coding) twice a week. We require them to demo what they've learned each Friday and many more nuances that simply browsing MDN won't give you.

In short, good coding schools are a shortcut to being a junior developer. They will learn how to learn to code.