I have to disagree. The title is an obvious clickbait, but even though I agree with some of your arguments, they are good for general learning and have nothing to do with online courses in general.

Udemy has tons of good materials. And udemy has bad materials, too. However, if you are going to make the best of a good course or not is up to you. Yes, online courses require discipline. But that's how learning new stuff works. You can surely learn a lot by coding, but you can't learn everything. Having someone to point out the best practices, how they feel more comfortable when creating new projects, their line of thought, their experiences is a valuable tool.