Remember: "There is no way to leave the EU once you are in." Or the Euro. Or the Eurozone. Or the EEC. Or the European Continent. Well, unless you have a really big motor engine.
as the latter: Greece benefitted quite a bit from EU subsidies since joining. you can argue about if the same holds true for joining the eurozone.
> The terms of the deal for Greece have been pretty onerous, you lose control of your currency with no equivalent upside.
No upside? What do you call a decade of easy access to super cheap credit? Also, these terms are not unique to Greece, no other Euro-zone country has control over it's currency.
A poison pill. It's like giving free booze to an alcoholic. It's certainly not kindness.