It's a valid point - if I were concerned that Jr. developers would parrot every line from the course to the ridicule of very particular Sr. developers I would have specified that the Virtual DOM makes React faster than if it were trying to directly use the actual DOM, all else being equal.
But since that wasn't a concern of mine when I made that video (it is far from the main takeaway of the course), I kept it as simple as it needed to be to get the point across.
But why even bring up the topic of virtual DOM in a course addressed at beginners? If you picture your target audience as so new to the field, why should they even care how React is working under the hood to change the contents of the screen?
Virtual DOM (unless I am mistaken) is a solution to the problem that React would have otherwise introduced. But surely, selling points of a framework are not how it solves its own technical problems, but rather what problems it undertakes to solve for its user.
But since that wasn't a concern of mine when I made that video (it is far from the main takeaway of the course), I kept it as simple as it needed to be to get the point across.