1) What exactly would I be wrong about? A good test for cognitive dissonance is comparing your predictions to reality, and I do not believe that I ever stated that BitCoin is inevitably going to become the most important currency in the world. I think crypto is great conceptually (which will never be not true) and that it may or may not succeed in the marketplace. Bitcoin itself may not succeed long-term even if crypto does. I acknowledge all of those things.
2) If crypto "fails", I'd say that the reason for the failure is important in making an assessment. If it fails because the technology is too slow long-term or not enough people choose not to use it for a very long-time, that's one thing that would be harder to argue against. If crypto fails because it's effectively legislated out of existence, that would be hard to see that as anything but a vindication of the concept.
3) For what it's worth, while I consider myself to be a fairly rational person, nobody is absolutely immune to cognitive dissonance. You should constantly check your premises and examine your past predictions. That's part of why I support the absolute right to free speech and debate ideas and play devil's advocate a lot.
4) I stand firm on one prediction. If some government out there decides to use some crypto for their central bank, they're going to have their media pump out support for it, and many former crypto opponents will be reprogrammed on the fly and take on a pro-crypto viewpoint without skipping a beat if they're told to.