[MargaretR]

The Greek debt was partly caused by tax avoidance/evasion.
People paid cash 'backhanders' for goods and services so that only part of the transaction was recorded for tax purposes.
Criminals operate a cash laundering system to conceal ill gotten gains.

I believe that these two misuses of cash may well be the reasons why, eventually, cash will be 'phased out'.
The abolition of cheques (delayed) was the first stage of the operation.

It may sound like a reasonable and sensible action to take, until you consider the implications.
Governments will know exactly how much you are worth,
where it is stashed,
how much you spend
and what you spend it on, both where and when.

This strikes me as rather intrusive.

Would you welcome 'the end of cash'?