I mean, I'm not sure it's done deliberately but... if I was trying to guarantee video gen was always 5 seconds in a consistent manner and the gen process was hi

I mean, I'm not sure it's done deliberately but... if I was trying to guarantee video gen was always 5 seconds in a consistent manner and the gen process was highly non-deterministic then if the resultant video would have only been 3 seconds I'd stretch it out, interpolate the frames, and then send it down the pipes. Another point to consider is that if my generative video system isn't good at maintaining world consistency, then doing a slow-motion video gives the illusion of a long video while being able to maintain a smaller "world context".