All money systems are a version of Europe’s Target 2, which is merely an interbank payments system for cross border transactions. When contained within countries, nobody even bothers to think about the way the system works. It’s plainly not going to matter, for instance, if a big trade and capital imbalance develops between the north-east of England and the South East, if only because there is a unified banking and fiscal system to intermediate. If there is a sudden rush of deposits out of the North East to the South, it makes no difference to the banks involved; their net position in terms of assets and liabilities is unaffected.