It's like being the guy who checks the Wright brothers' calculations, finds them correct,
Perhaps more like the Wright brothers were planning to figure out how to land the plane after they throw it off a cliff. And your example throws out the benefits of not signing up for cryonics, which are a major factor for me.
Note that if Wright brothers didn't believe that there was a considerable chance of the plain not crashing, it would be a bad investment to build the plain in the first place. The question is about the cost: does the current state of knowledge support the positive outcome sufficiently to think of designing a plane? To design a plane? To build a plane? To perform an experiment, risking its destruction? To test-pilot a plane, risking one's life?
The same goes for cryonics, here you risk something like 100 bucks a year.
My girlfriend/SO's grandfather died last night, running on a treadmill when his heart gave out.
He wasn't signed up for cryonics, of course. She tried to convince him, and I tried myself a little the one time I met her grandparents.
"This didn't have to happen. Fucking religion."
That's what my girlfriend said.
I asked her if I could share that with you, and she said yes.
Just so that we're clear that all the wonderful emotional benefits of self-delusion come with a price, and the price isn't just to you.