But that's the point: the assets they have are not safe as treasury bills, and in a significant part they are backed by risky assets, including other stuff that

But that's the point: the assets they have are not safe as treasury bills, and in a significant part they are backed by risky assets, including other stuff that depends on crypto, so if ever there is a bank run they will not be able to keep up with the redemptions. The fun bit is that few can actually redeem, and most of those who could have a vested interest in never doing it anyway!