The inflation targeting framework allows the exchange rate to be determined more fully by market forces than under a policy framework that tries to fix the currency. This has various advantages, with perhaps the key one being that movements in the currency help to moderate the very forces causing the currency’s value to move.
When the currency depreciates, moreover, the costs to some economic agents are balanced by gains to other agents, like exporters. This in turn reduces the cost of international contagion to the domestic economy. This is a lesson learned well in some Nordic economies.