Anyone who takes the Santino line needs to explain what it is about the EU institutions we are leaving, and Greece, that they object to. If they don't distinguish on Greek debt and sustainability between IMF (very hawkish), ESM (less hawkish), ECB (self-serving), and if they don't say what specific things they wanted the European Parliament, Commission or Council to have done differently, they haven't contributed anything more meaningful than any other kind of hand-waving Brexiteer.
Greece is a reasonable argument against joining the Euro. Not enough of one, in my view.