It might be helpful if you gave a link that explained what countries have what you are describing and how it works.
You state in the comments that it would be useless to someone to steal your ecash card because they need the PIN to use it. Surely this is naive. You need a password to access many bank websites, and yet this does not make them 100% safe. Scammers steal passwords all the time. A common scam today is to put "skimmers" inside or over the credit card slot at gas pumps or ATMs, or to intercept wireless communications. Surely if such ecash cards were common, scammers would figure out ways to beat whatever security they had. Ranging from super hi tech password cracking to putting a gun to someone's head and saying "tell me the PIN or I'll blow your brains out" to all sorts of things in between.
How would these ecash cards be anonymous? This gets back to how you suppose that these cards do or could work. If the amount of money available to be spent with this card is stored in a bank somewhere, and every time you use it the bank checks its records, verifies that you have that much money available, and then subtracts from the balance, then the bank must know who you are, or at least know some sort of ID number for the card, and have records of every place you used it. If you bought the card or added money to the card through your bank account or with a credit card, then they know who you are. I suppose you could have a system where people buy these cards with cash and do not show any identification.
If the bank does NOT validate and record every transaction, how does anyone know how much money is left on the card? If the number is stored electronically on the card, there's a very obvious scam here: Get a machine that can read and update the data on the card, and change your balance to a million dollars. Maybe there's some sort of encoding or encryption that makes this hard. Presumably every store where you might use the card has to have a machine capable of changing the balance, so it's not like the hardware would be hard to obtain.
Someone on here said that such cards would have to be issued and managed by the government or there would have to be fees to pay for the system. Of course if the government did it that wouldn't magically make it cost free, it just means you would pay through your taxes rather than paying at the bank. Even if the government could do it just as efficiently as private industry -- pause here until the hysterical laughter dies down -- I don't see why taxes are preferable to bank fees.
Personally, I very rarely use cash. I pay for almost everything with either a credit card, which I then pay the balance every month, or with electronic transactions. I have a small business that I moved to another state 10 years ago, and it wasn't until last year that I finally got around to ordering new checks with the new address, because in the intervening time I only wrote 2 paper checks. (For those 2 I crossed out the old address and hand-wrote the new address, which seemed excessively tacky looking, so I finally did get new checks. I don't think I've used one yet.)
So I think if anyone would be receptive to this idea, it would be me. But I'm struggling to see how what you are suggesting is better than a credit card or a debit card. I'm willing to be convinced. It's quite possible that I don't understand how these cards you're describing work. (I looked up "Europe cash cards" and what I found didn't explain much about how they worked, not enough to make clear what the advantages are.)