Snowden asserted and still does that he deleted his own copies once Greenwald et al. got their copies, well before he had to flee Hong Kong and ended up trapped in Russia.

Remember, it was the US who trapped him in Russia by revoking his passport -- an international crime in and of itself, rendering him stateless which no country should do to its citizens, no matter what crimes they have allegedly commited -- and he had no intention of ending up there; he was trying to get to Chile I believe, and the EU did the unprecedented step of force-grounding their equivalent of Air Force One, with their president on board, thinking Snowden was a passenger.

Imagine if the POTUS had his plane accompanied by fighter jets to force-land in any other nation. The response would have been explosive, literally. Such hypocrisy that they just wave off other nations' sovereignty and diplomatic norms on the treatment of foreign leaders so easily.