There is a guarantee that the value will be returned with interest, unless there is an unfortunate event that may destroy the value then their will be an understanding. The money cannot just be legally "seized" unless there was an understanding that the money was meant to be a charitable contribution.

I am discussing store of value protection of wealth, as I see it the same principles apply, be it states or private wealth. There may be different reasons why there are no large withdrawals naming a few the fact that large withdrawals may result in seizure to make examples of individuals. Also there may not be very good options with good ease of exchangability but with enough incentives and fear individuals and entities wanting to protect their wealth can develop creative alternatives.