Another thoughtful essay <https://www.schneier.com/blog/archives/2019/02/blockchain_and_.html> from the well-known computer-security guru: Trust is essential to society. As a species, humans are wired to trust one another. Society can't function without trust, and the fact that we mostly don't even think about it is a measure of how well trust works. .... Most blockchain enthusiasts have a unnaturally narrow definition of trust. They're fond of catchphrases like "in code we trust," "in math we trust," and "in crypto we trust." This is trust as verification. But verification isn't the same as trust. .... Any blockchain system will have to coexist with other, more conventional systems. Modern banking, for example, is designed to be reversible. Bitcoin is not. That makes it hard to make the two compatible, and the result is often an insecurity. Steve Wozniak was scammed out of $70K in bitcoin because he forgot this. .... Honestly, cryptocurrencies are useless. They're only used by speculators looking for quick riches, people who don't like government-backed currencies, and criminals who want a black-market way to exchange money.