Where does the blockchain come in? As long as you have a signature from the central authority over two conflicting transactions, you can prove it has defrauded

Where does the blockchain come in? As long as you have a signature from the central authority over two conflicting transactions, you can prove it has defrauded you. Blockchains specifically solve decentralized consensus. It’s expensive and slow compared to using a central authority, but the advantage is that the system doesn’t suffer from a central point of failure.