I think you are talking about something totally different. For any training, professors will review their students, even after a thesis defense, a student should retouch some part of its work. That not means that the work is not from the student. I have followed an in person 5-year engineer program to become a network engineer and at each step, there are some tests and validations reviewed by teachers until after the training the student has the ability to work on his defense as a network engineer. And I think the Udacity MLND online program is the closest to these in-person programs.
For our subject, a review is necessary for someone who is learning. How do you want someone who is learning to know if he could get a better result even if what he has done works? And after you have learned and mastered the subject (state of the art methods in the field), you could apply your knowledge on a project of your choice (the capstone), which is equivalent to a master of engineering thesis defense for the online program. But here, it is focused on professional proposal and paper writing (research oriented).
After that, you have research abilities to work on your own on any other project in the field of Machine Learning.
So, for lifelong learning purposes, a graduate student from the MLND could still follow other online courses. This is why I appreciate your list. And from your list, the SDC is one of the fields I plan to learn later.