There is nothing special about cash to make it valuable above bank credit

In a fiat economy the physical nature of the money is not the crucial feature, instead it is the contract or promise encapsulated in the unit of account. Cash is arbitrarily valuable, it can be used to cancel a tax liability if there is no disincentive against paying taxes, and no one goes to gaol then there would be no value in a fiat currency. If it becomes too difficult to collect taxes then the Government will lose power and the underground black economy will thrive.

Given that there is nothing inherent in cash which gives it value, only what it represents then we see that (it makes sense that) bank credit has the same value since it performs the same role, being able to extinguish a taxation debt. There is nothing special about cash to make it especially valuable as compared against bank credit.