In my experience, 'classic' electronic currencies follow this general pattern: 1) you obtain them from a bank, 2) you pass it to another user, and 3) that other user brings it back to the bank.
At best, the bank can't see where the receiving party's money came from. But still, every 'coin' in circulation goes from bank -> user -> another user -> back to the bank.
The big difference with cash is this: using cash, money can pass from #1 user to a 2nd user -> 3rd user -> 4th user -> back to the bank. With the bank having no way to figure out what happened in between. Transfers from 1 -> 2, 2 -> 3, and 3 -> 4 need not involve a bank at all.
To me, anything that fits the 2nd definition is interesting. Anything that fits the 1st definition, is just electronic payments in the classical sense that eg. governments might be monitoring every single transaction. Regardless of implementation. So if in this case, Amazon = 'the bank', do we even care, if that currency clearly isn't 'electronic cash' ?