"each MP4 file was likely to be about 3GB. (...) Also, it’s not easy to watch a file like that. You’d need to download the entire file first to even be able to watch it"

I dont think that's true? Even with moov atom at the end of the file, browsers just figure it out, as long as the server supports http range requests. And I suspect the size could be much smaller, given the low resolution of Video8 footage, but maybe author did the reasearch and compression would take too much time.