Well probably because that's a very creative way to spread their marketing message. And because it is very well done technically as well: stitching video segments in an order that depends on user action, without any visible transition, means they put a lot of work on that.
So I don't think general UX/video guidelines apply in this case, even if they're valid for most cases for online video.
Sure, they should probably have used an adaptive bitrate video for users with poor connection, because here they can't pause and let the video prebuffer for a while. Other than that this is pretty impressive
The UX of this app is quite innovative and immersive.
You are applying heuristics that are true for man websites, but don't apply here. I would say this is more like a simple video game. It would make no sense for example to have navigation control over this video. That is the point, you can't just rewind to before the accident occurred.
So I don't think general UX/video guidelines apply in this case, even if they're valid for most cases for online video.
Sure, they should probably have used an adaptive bitrate video for users with poor connection, because here they can't pause and let the video prebuffer for a while. Other than that this is pretty impressive