Words are more minimal and efficient than voice (think of the passage from oral civilization to writing civilization).
After the introduction "So the thing I have been thinking about a bit recently" with the classical youtuber voice tone I just stopped the video (didn't want to check out if you - or the other guy, I don't know, don't care - were going to show me the product or spend 7 minutes on storytelling) and went to the play store to see what it actually does (since a quick glance to the page didn't show any screenshots or explanation).
Now I am installing the thing :).
While text is certainly more efficient than voice, I think the (very large!) differences between oral civilization and writing civilization are more down to the fact that text is more permanent than voice.