Some time about 440BC, the Athenians decided to make all these people get rid of their own currency, with their own national emblems, and use Athenian "owls" instead - in fact some of the public notices laying this down, still survive, inscribed on stone around what was the Athenianempire.
Another reason is they feel they have contributed to the project historically - not just through Athenian democracy but in the liberation struggle against the Ottoman Empire, and through the heroic resistance to Nazism which still haunts the memories of elderly people here.