Every few months, my credit card blocks one of my purchases because its statistical algorithm decides it looks sketchy and wants me to respond to a verification

Every few months, my credit card blocks one of my purchases because its statistical algorithm decides it looks sketchy and wants me to respond to a verification email. How is this any more trusting? Both systems recognize the existence of fraudulent actors, and handle the problem in different ways. Blockchains use cryptographically-signed transactions, so merchants get no information they can use against you. Credit cards hand your credentials over to every merchant and try to fix their fundamental insecurity by flagging unusual transactions, insuring against losses, and issuing new credentials when bad actors get them (which brings lots of associated hassle, that I've gone through a couple times in the last few years). Bank transfers handle the problem by simply delaying full access to the money, at least for larger amounts, until banks on both ends have checked everything. The same applies to more complex systems. Blockchains try to build systems with extreme transparency and security (and sometimes fail at that). Traditional finance builds systems reliant on centralized actors, and adds lots of regulation, oversight, and incentives such as criminal penalties to keep those actors in check (and sometimes fails at that). We certainly should strive for a more idealistic future. But legacy banking/finance is not doing that. Blockchain platforms at least provide the possibility of building something new that's better; on top of an open trustless platform, you can build your own system assuming whatever level of trust and altruism you like. Two examples on Ethereum: optimistic rollups are more scalable second layers, in which withdrawals work more like bank transfers: withdrawals aren't cryptographically verified, but have a delay during which anyone can submit proof of fraud. A more idealistic example is Gitcoin, in which people donate to public goods and the money is allocated with a quadratic funding system.