Banks do not operate in a closed microsystem (though they might like to).  Value is ultimately social. As someone pointed out - the value of a mobile phone when lost and thirsty  in a large un-networked desert is zilch. The ownership or income worth of commercial or industrial property, for example, is not in the cement. It's in the space.

You can't be me, I'm taken

I think in this case it's more like "assets worthless as long as the market has no liquidity - and pockets not deep enough t make it through".

Keynes said "the market can stay irrational longer than you can stay solvent".

A vivid image of what should exist acts as a surrogate for reality. Pursuit of the image then prevents pursuit of the reality -- John K. Galbraith