One of the things that I see coming up over and over again is quantum computing. What I read about how this relates to crypto currencies is that with quantum computing, it will be possible to figure out the keys to the coins. In fact, it was even stated that a key didn't have to be exact, but close enough. This would mean that even those people who store their keys on a thumb drive that is buried in the yard might not have their coins when they go to access them. Its one thing to break into one of these crypto sites and steal the coins they have, but its a whole other ballgame when you don't even need to steal the keys but mathematically brute force your access to the coins. Even if this technology is a few years away (which is might not be), the idea that someone could steal your coins by just using quantum computers is a very real threat. I prefer the bank having my money where I have some recourse for any thefts and am willing to give up anonymity and some slight deflation for this privilege.
I hear the same stories from my son (who is working in the IT industry). But also apparently something about controlling 51% of the coins as apparently checks are not done for 100%. Apparently controlling for 100% would soon require a lot of time, energy and equipment. Who controls 51% can apparently decide what is true and what is fake as they have the 51% to confirm the transaction as good. Just what I hear, not telling it is true, or that I even understood it right. I am not smart enough to follow my son. At least not in that area. But I can still beat him in trading. That's why most people will never accept crypto's as currency. I posted that already earlier.