The value of the currency board is that it puts domestic monetary policy on automatic pilot, and guarantees that policy will move aggressively to support the fixed exchange rate when it is under attack. The markets no longer have to worry about the willingness of the policy authorities to adjust interest rates aggressively enough to support the currency.
Banks have begun to experiment with other models that can give both them and the borrowers the assurance that the repayment is going to be back on a firm basis. The Committee has mentioned an approach outlined by Ulster Bank, and on the face of it that approach seems to have most of the ingredients needed to be considered sustainable.