why do people go for online tutorials?
From what I have seen, courses are successful when they act as a convenient training program which helps users get started with a technology/domain with minimum effort. There are already a lot of information available and easily accessible, in the form of books and papers (many important papers have an archived version, but not all of them have one- thus, some of them are completely free). But the number of people who will directly benefit from such sources are very less.
The small group of people who benefit from these primary sources will have to make the material even more accessible, to reach a larger audience who finds it hard, or cannot learn directly from research works. This goes on, as new groups of people work towards simplifying the material even further. And finally this reaches the majority who rarely benefit from reading papers or reference books. Tutorials target the lowest level and are supposed to be as easy as possible, enabling practitioners in the field to easily adapt to the new way of doing things.
Thus, as long as the instructors break down the material quite well and explain everything step by step without having the users do a lot of work, the course should become a success. Yes, I do agree that there must be some level of beta testing. But there are users who would volunteer to pay and sign up for new courses that are marked as "beta", as long as it covers everything they need and they are given a trial period to evaluate if the course will really benefit them.
But the course mentioned in the above article is quite suspicious, if whatever that was said was true.