Which is why I made this comment on a thread about a new digital currency that according to the title is untraceable, and not a thread about BTC.

Don't rely on paper cash being around for that much longer either - http://www.zerohedge.com/news/2016-01-23/norways-biggest-ban...

I moved to Denmark a few months ago, and have been asking a few people whether they'd prefer cash.

Street food vendor: no, he preferred a card.

Taxi driver: no, but he didn't want to take a card either, only a bank transfer from my phone. My account isn't set up for that yet, so he took the cash, then didn't have the 5kr change.

Supermarket, exact change for a single item: I delayed people behind me, the machine used to count coins didn't accept mine.

Café, for a single soft drink with exact change: I didn't ask, but the man dropped the exact change into the empty coin tray.

So the result is I still have most of the coins which a foreign friend left behind after visiting in December.

You can't compare Paper Cash to Bitcoin or Crypto-Currencies.

You can't take $5million cash through Airport security. You can take $1bn bitcoin brainwallet through airport security, and nobody will ever notice.