In a world where videos are still sent around as multi-megabyte gif files, and audio clips are still distributed with a random slideshow on YouTube, I think a lot of users aren't so bothered about efficiency - they just want the simplest thing that works.
Lots of music is most efficiently stored as MIDI, yet how many songs on iTunes are midi?
For video, raster is king because it works for everything.
- Our videos use about 1/100 bandwidth of a video. This matters for rendering (fans running when watching HD?) and to people who live in places with shitty ISPs like in Germany
- It is rendered and thereby crisp as a Pringle
- No codec needed as we render it as html
- When you pause a video you actually have the text there, not pixels. For programming that allows you to copy and change things!
- We store the context it was recorded in (dev environment) so you can change and run code in the "video" itself. This changes the pedagogy you can do in a video to be more interactive and hands on.
Random link with some pricing information for Africa [1] claims prices are up from $0.50/GB.
[1] https://kenyanwallstreet.com/mobile-data-pricing-2020-report...
(As an aside, MIDI is a useful format in its own right, and is still alive and well in the music-making world, even if from a technical perspective it's sort of outdated in 2020.)
Switching to H265 or AV1 is way more compelling in practice because it works for everything, it's hardware accelerated, the decoders are off-the-shelf, and the quality is significantly improved. A modern GPU can both encode and decode H265.
While storing music as its component instruments is indeed size efficient, converting existing music into MIDIs using some ML/AI algorithm is not yet effective. Vectorly seems to convert _existing_ raster videos into vector ones using some combination of computer vision algorithms.