Stablecoins are dangerous because they have the potential to change the current selection effects on the elite. For one thing, stablecoins subvert the ability of the Federal Reserve to print money and give it to their friends at Goldman Sachs et al --- normally this is supposed to result in their friends have a larger fraction of money than they previously had. You start with 1 dollar, David at Goldman Sachs starts with 1 dollar, you each have 50% of the wealth in the "nation." David and his friends start printing themselves money, soon they have 99 dollars and you have 1, and you can't compete because they'll lock you up with violence for being a "counterfeiter." That's how inflation works.

When there's stablecoin, you just put your dollar in stablecoin before they print the money, the dollar inflates, stablecoin goes up proportionately, you spend the stablecoin and things remain fair.

This obviously curtails the ability of the ruling class to reproduce itself. More than that, if the pool of people getting billions through stablecoins is more random than the pool of people who got rich on the dollar, then the ruling class will change to be more representative of the population as a whole.

This could cause massive cultural changes, consequently.