Those hundred years won't exist for the dying. I would personally find comfort in knowing that I will feel waking up right away into a technologically much more advanced world
It's really debatable if religious people actually believe in eternal life. If they did, they would immediately see that their behavior drives them straight to eternal damnation.
They don't seem to care about that, and the only rational explanation is that they don't believe there's anything after death. They're nihilists. We all are.
Even if the tech doesn't work, I wonder how much relief from suffering the idea that it will in a hundred years could be