Well this metaphor is actually quiet apt for the idea of the block-chain though it is not a hologram technically. With a Hologram, things are not decentralized because there is a source which creates the refraction. Though one could argue that Light itself is decentralized because it moves at the speed of causality which means that all of the information in a beam of light should be on all of the protons at once. A perfect Quantum computer should be able to read information at the speed of causality.