From reading these posts I understand that we're a lot further down the road to a cashless society. It rarely happens that I use cash. Sometimes I go a week without handling any. Almost everything I pay via debit card and electronic wallet (I do have a credit card, but I only use it abroad).
Even the homeless here have a debit card. That is because they need a bank account to get their monthly allowance and the only way to extract that is via an ATM.
From my viewpoint there are a couple of advantages and disadvantages.
One major advantage for me is safety. I never felt comfortable walking around with a few hundred dollars in my pocket. Now I only have a small piece of plastic which I can block in a matter of minutes.
Another one is efficiency. I don't have to go to the bank anymore before going shopping. I don't have to wonder whether I have enough money or enough change etc. I can always get a printout to see how I have spent my money that month or week.
A disadvantage is that it becomes easier to overspend. You're never short of money until it runs out. For me that is no problem, because I'm not an impulse spender, and I am good in keeping track of my finances. If anything it makes maintaining my finances easier. However I can understand that it is a problem for some.
Another problem is for the elderly and handicapped. Elderly people have often problems with understanding these systems and for the visually handicapped operating them is difficult. Since there often is no non-electronic backup they have to rely on help from bystanders. I can understand that it is frustrating not to be able to do the simplest of things like getting a train ticket without any help.
Then there is privacy. I guess that we have no other option than to to trust those who have access to the system. I have to admit that that is not the easiest thing to do.
About undermining the currency system. My father has some old german banknotes. this example is a note which was overprinted from 1000 to 1.000.000 reichsmark during the inflation.
http://www.germannotes.com/img-bn/1922- ... 0&1Mrd.jpg
For me that has always been a warning that you cannot trust money per definition, whether it is paper, coin or bits and bytes.
If anything I would say that the only argument for maintaining cash would be that it involves more human interaction. Efficiency is one thing, but it should not lead to a world where we only communicate with each other through layers of glassfiber.