Yep, this is time and time again what's made me give up on MOOCs and I say this as someone who has done formal education online (I did an additional degree in my spare time with the UK's OU some years back).
Videos are mostly shit for learning, if I don't get something I want to be able to just re-read the paragraph, not dick around with some video player trying to get it to the right point again so I can listen to some monotonous or accented person drone on - it's not that I have a problem with accents, it's that it's an additional distraction when you're trying to take something in and learn - I want to focus on what I'm learning, not have my mind stray off about how the guy in the video just used some amusing (to me) American pronunciation of a word or something.
It strikes me as sloppy, people are doing videos so much now because it's easier to slap your webcam on and ramble on, turn it off and upload it, but learning materials need to be better than that, they need, like a book, to be edited, to be split into proper paragraphs, to be indexed.
If they are, then I can read a few paragraphs on the train, but I can't really be bothered to prat around pre-downloading videos, or trying to stream them over and unreliable 3G connection as the train goes through tunnels. I don't have time for any of that- I just want to be able to load a quick bit of text and read it at my own pace, re-reading it if need be.
This modern lazy trend towards videos is killing information, I've worked places that block video streaming in the past and if your API explanation is a video then that leaves me documentationless, of course I can probably go and get that unblocked sure, but I could also just go to one of their competitors that isn't so lazy and boneheaded. Not everyone has the capacity or even wants everything as a video which isn't to say as you point out that they have no place, sure they do, sometimes videos do work - but not for lectures, rarely for conveying large bodies of technical information.
This is why I've completed an entire degree with distance learning but have simply never finished an EdX course or similar despite many of the courses being particularly interesting. The idea of these MOOCs is absolutely great, it's fantastic. The implementation to date? shockingly bad.