Earlier quoted context omitted.
This CSS animation is just the backup in case the javascript doesn't load at all, really. After 8 seconds, the page gives up trying to prevent the flash of unstyled content and just renders, regardless of how bad the styling is. It also includes a block that renders the page immediately if javascript is disabled. The 8s thing is for network issues. Graceful degradation. Lots of documents (amp or not) use the same "hi…
> Lots of documents (amp or not) use the same ... trick Perhaps luck, but I have never encountered one that is so hostile about it with nearly 10s wait outside of AMP. I've rarely encountered a second or so's delay, but two or three sites including a large one that have the massively excessive AMP delay. So to call it the same trick seems like a stretch from a user annoyance point of view.
It annoyed me as well before, though I realized as I stopped going there that this is for the best... for both my sanity and the websites bottom line.