you would want to trust your money to some group that is distinct, relatively weak, and universally despised.

That way you don't have to worry about them stealing it and trying to usurp power (if they ever attempted it there would be pogroms).

It's not very nice but in a realpolitik way it's kinda useful to have a racial minority group that can be trusted to watch over certain elements of power since they could never wield it directly.

A christian second in command may try to stab you in the back and take control (we're talking middle ages here). A jewish one would not since A) no one would follow him and B) any period of anarchy means that he will likely be killed.

But at least Mary Steenburgen got an oscar out of it.

it all?