Eh, having studied prions (and related conditions, like diabetes, and alzheimers) I think it's just because they're "exotic". If I just called prion disease "contagious alzheimer's"... You'd probably be more scared of ebola, because the way that it kills you is more painful, and you're going to be isolated, so you will die alone except for by people in spacesuits, with the only major difference being that the prion diseases are currently incurable. But if an agent is being successfully weaponized, infrastructure for curing more conventional conditions would be stressed to the point where you would be likewise incurable (we were stressed in many places by COVID-19 and outside of the risk that you go critical, that is very much not a scary condition for a huge chunk even of people that get it).

I think the "completely incurable" aspect of it is the scary part.

I'm not AS concerned about something like Ebola, because while being horrible, it's horribleness is self limiting because people die (relatively quickly) before they can spread it too far.

On the other hand, weaponized vCJD could have a population die off en masse years after they're infected. Since it can be transmitted via blood transfusions, it'd essentially shut down blood donations (although if everyone had it, I guess that wouldn't matter). Also just the fact that prion diseases can cause psychological symptoms make the implications different from something like a classical infectious disease.

> On the other hand, weaponized vCJD could have a population die off en masse years after they're infected.

Maybe the infection could use genetic mechanisms so that the infected pass it on to their children. Maybe this already happened thousands of years ago. X-Files Theme.

Personally, I would definitely choose to die of Ebola rather than Fatal Insomnia. You get slowly driven insane by your inability to sleep. Truly one of the worst ways to go.