No they are not as supply is constantly inflated (melting ice cube). Do yourself a favor and look up the maximum and average survival times of currencies historically.
Lets add counter party risk on top for no gain?
Agreed, and to transfer wealth from the productive class to the parasitic class (politicians and all the professions that only exist or are as large due to politicians eg tax advisors).
That's a feature not a bug. Frequent small crises every few years is the natural way of an economy. All central banks do is block the economy from going through these release cycles taking out the poor allocators of capital. Their continued existence, financed through direct and indirect transfer of capital, supports Malinvestment of capital which comes with a huge societal cost (opportunity cost).
Central banks are a core tenet of communism. Free societies by definition cannot have central banks as their very existence is coercive and exploitative. The US was much more free until the UK bankers Trojan horsed the Fed into existence in the US (I'm European btw, the oppression and stagnation the founding fathers fled from, unfortunately you were followed there by our crap institutions centuries later).
What does "run on" mean in your mind? In mine people should be free to use whatever medium of exchange, store of value and unit of account they choose and not be coerced into one or a few. Enforcement that exists now through enforcing acceptance of a specific fiat currency, enforcement of tax settlement in a specific fiat, forcing tax calculation with a specific fiat (eg paying capital gains on a,loss,of purchasing power through inflation) and restriction of what assets can and cannot be owned by a private individual is barbarous.