In general, the more people cooperate, the better the results are overall. The downside is that the more people cooperate, the more they can be taken advantage

In general, the more people cooperate, the better the results are overall. The downside is that the more people cooperate, the more they can be taken advantage of by defectors, by bad actors who decide to harm the public good in exchange for personal benefit. I absolutely agree that being able to trust particular actors is a huge benefit. Part of the problem is language. "Trust" isn't just trust in a particular actor's intent, but also in their capabilities to carry through on a promise. In order to trust somebody to carry out a promise, you need to indirectly trust on others not to interfere with that promise. In this case, if you don't trust the US government to handle currency, then you certainly can't trust a publicly traded company that is beholding to work within and has assets that can be seized by the US government. If you assume ill-intent on the part of the government, then there's no reason to assume that a smaller actor wouldn't be influenced by the government. In this case, I trust the US government to manage currency well, because it is in its best interest to do so.