It is a point being made to show that a Greek exit from the eurozone really does mean unrecoverable  debts for the rest of Europe.

Beyond that, Citigroup has argued that the removal of ELA automatically creates a legal liability for Europe that absolves Greece of any debt.

I would also point out that the debt conversion in 2012 changed Greek debt from being Athens based, without any collective action clauses, to London debt that required a % of creditor agreement in the changing of any terms.