The main reason it is a differentiator is that centralised money understands that its purpose is to be a system of social credit, so reversibility of transactions is just an acknowledgement that there is enough evidence to prove that this particular individual owns this particular sum, so it should go back to them. It is actually a much better and more honest system than the blockchain, because it doesn't treat money like a tangible resource in and of itself that can be "lost" which would be a much older and dumber way of doing things.