My English is not good enough to make these with voiceover, and the ones with subtitles/explanation boxes are, IMO, boring to watch.
So I really prefer to explain it writing, and to direct questions from users.
But, if someone wants to help with it, these demo videos would be great to increase the public exposure.
Yes, I'm the one who knows all the program functionality, but almost all the software demo videos we can find all over are made by users, not developers.