If you're looking to make money / provide more value with this service I think the angle you should try for is Video to Blog Post.

The transcript is fine but I'm not quite sure what problem this solves. Whereas if you were able to take the transcript and spit out a file that was broken into sections (based on YT chapters) and with an attempt to automatically clean up the grammar and remove the "um" style fill words of the spoken version I think this would hit in a very different way.