Collateral would drastically raise the bar for this operation, because the operator would be forced to deal with the risk of exchange default instead of Nu. This operation is intended to be cheap and risky and make shareholders painfully aware of the gaps in the current liquidity model.
T3 can be collateralized because the custodian takes little to no risk and so the only thing they are collateralizing is the possibility that they may run with the funds or make an operator error, both of which are entirely within their control.
