Why is this a "fiction" and why do you need banks? Why do you dismiss Bitcoin? Please explain.
BTC can work without trusted 3rd parties, and transactions can be performed in a completely anonymous way. Not every transaction requires or even benefits from these qualities, however. For Joe User's grandma to use BTC, there are going to need to be trusted 3rd parties (e.g. banks) to manage the minutia of transacting. These 3rd parties will make things simple for grandma, and ensure that she doesn't get screwed.