Lots of youtube videos are not the well-organized presentations you describe, but instead have a minute or two of good information with ten minutes of meandering asides, background you already know, and other fluff. Some are well-disguised clickbait. A good summary prevents a lot of time wasting.

As for the good videos, I can't watch them all. If I can skim a good summary, I can decide whether, for me, this video is worth watching, or ignoring, or just reading the summary more carefully.