We might only be pulling up jewelery in the future.
Though cash will never die. People will find another physical medium for quick person to person transactions (especially the underworld, and rebels of society).
A likely candidate would be gold, you can get 0.5g amounts sealed, not much larger than a credit card.
So I predict a rise in the gold price
(silver would also rise).
There has been a rise in the use of cash alternatives in EU countries that suffered from the Euro debt crisis (Spain & Greece in particular). Some returning to the currency used before euro adoption - might be good to have people carrying around nz predecimal silvers.
Can anyone think of other cash/gold replacements?