The basis of blockchains is that you don't need to trust. You run the algorithm, you run it faster than everyone else and you got a coin to spend. It's all publicly, cryptographically verifiable. As long as everyone agrees on which blockchain is the real one nobody can take away your coin.
This trustlessness is an important selling point in a world where people don't trust each other, their institutions, their governments, especially after 2008 when it was clearly demonstrated that the financial institutions we depend on are being run like criminal organizations, to this day and with zero consequences for the criminals. So here comes technology to save the day.
Crypto economies can exist because blockchain technology eliminates the double spending problem. The problem of course is that although blockchains can restrict people from spending their coin twice, they can't restrict people from committing the rest of the crimes, including scamming, social engineering, insider trading, pumping and dumping and other market manipulations. Every crime in the book, since crypto economies are not meant to be regulated. Outright replacing the blockchain with a different one also happened to Ethereum. The perpetrators range from lone social engineers to companies like a16z doing white-collar crime on an industrial scale. Trustlessness basically devolves into a bigger fish eats the smaller one system, and Ponzi schemes in which people are left holding useless crypto assets. It's all about stealing USD from bigger fools. Bonus points if you manage to convince them to never sell their cryptocurrency back, which is why crypto is being pushed as an utopia, as a solution to everything. It's the future of selling art (NFT) and hosting websites (Web 3.0), even though it is obvious that blockchain technology is not especially suitable for any of that. It can only really eliminate the double spending problem.
Unfortunately trust, and more importantly oversight will always be required. You can't avoid it as long as there are humans involved. We have to fix our institutions instead of trying to reinvent the wheel. There is nothing fundamentally wrong with them, most of our problems can be accounted to industries and interest groups manipulating the system to their own benefit, more usually than not by hindering regulatory effort.