It's not a natural tendency for human beings, it's a literal requirement for a system that cannot operate with some form of trust. When that trust is violated,

It's not a natural tendency for human beings, it's a literal requirement for a system that cannot operate with some form of trust. When that trust is violated, there needs to be a meaningful way to resolve disputes. Legal tender (as in government issued) has literally thousands of years of experience with this problem, and it's no mistake that the entity with a monopoly on violence (government) is expected to resolve this kind of dispute - because resolving it may very well require violence. The problem of course is that you're at the mercy of the arbiter resolving the disputes, but moving to crypto doesn't remove the need for an arbiter, it just removed absolutely all the legal safeguards and requirements for that arbiter. Turns out most of the "Source of trust" in crypto are scammers.