But the FCO advice on their website is subtly different to that in the article:
https://www.gov.uk/foreign-travel-advice/greece
"The currency of Greece is the euro. When travelling outside of the UK, you should take more than one means of payment with you (cash, debit card, credit card). Make sure you have enough money to cover emergencies and any unexpected delays."
Does that sound like anything more than routine common sense no matter where you're travelling to?