The banks are closed and Greeks unable to buy Bitcoin.
so they still can take a tiny portion of their money and buy bitcoin with those
but they will probably need that amount to survive, nobody in their right mind would buy bitcoin instead, seeing the utterly critical situation
Even if they buy bitcoin, who is going to exchange them, still large population of Greeks unaware of Bitcoin, for instance.... old and common people, it is a long procedure that to first explain about Bitcoin then how it's works and other things to them.