I can usually read 10 minutes of spoken content in less than 3 minutes. Accompanying video is often useless, unless there are specific diagrams or illustrations/photos. I don't need to see someone's face moving to absorb the info. Probably lots of people out there with similar gripes.
I didn't create the tool, so I can't claim to know the author's intentions. To me, this would be very useful in a variety of circumstances:
- the 15 minute video containing 3 minutes of useful information
- tutorials that you're trying to follow step-by-step that have been tightly edited such that actually doing each step while following along is impossible
- the video equivalent of listicles in which you're really only interested in the list, not the padding
- quickly getting an idea of whether or not it's worth your time to watch a lengthy video by quickly scrubbing through the content
