Usually the governments don't have a choice. The people simply decide not to use the local currency. And people generally care far more about stability, ease o

Usually the governments don't have a choice. The people simply decide not to use the local currency. And people generally care far more about stability, ease of movement and reasonably stable inflation over some control which they never experience directly. And since this ends up being a parallel grey market that is outside the taxation and financial control systems it's better not to fight.