The difference is enormous: in one case, you don't need any centralized N entities, just a big percentage of the network, whoever wants to participate, runs the protocol and there are no 50 institutions / companies that can block it without reaching the majority of work / stake. In the other case, you are delegating the consensus to a fixed amount of parties. Now, we against the crypto / blockchain shitstorm advertised the alternative of old-style federated consensus with N trusted organizations for years and years. And now, no: you can't say, this is a form of blockchain. You admit failure and acknowledge that classical consensus was good enough and even better in most cases.