Forget monetary theory for a minute, and think only about the technical/engineering stuff: is Andrew Lainton basically right about this? Can something like this be done quickly and cheaply, without too much danger of counterfeit and fraud? (I don't know, which is why I'm asking.)
If you introduce a new money, you want to do it quickly. But not everyone has a bank account, and I read that it takes months to print up a new paper currency. So unless the Greek government secretly ordered a big printing of Drachma notes when it first took power (which I doubt), Greece reverting to the Drachma is different from Argentina breaking the peg to the US dollar, because Argentina already had the Peso notes.
But technology changes. The new currency doesn't have to be on paper. It could be preloaded electronic payment cards.