If you have been into teaching you would realize that there are different kinds of learners. Some prefer verbal material, others prefer more visual, while some others like written material. The vast majority however prefer a combination of the above.

While you can pour over tutorials on how to use Emacs; just watching a video of a power user using Emacs gives you a different impression. It is really a completely different experience.

Sometimes it is faster to produce a set of video tutorials than to prepare well-written documentation. Hence they make a call. However, I agree that written documentation is the best medium for long term (i.e. smaller, searchable etc)

So, rather than asking for one medium of instruction to stop, I would rather encourage the plurality. Let the end-user pick and choose whatever he/she likes.