[cgh]

Yeah, exactly. These permissioned blockchain implementations rely upon some centralised source of trust (eg the government, network permissions, etc.) and I don't see exactly what distinguishes them from a distributed ledger. The core innovation and the whole point of blockchains is that they are permissionless and trustless. Or am I missing something here?

[wslh]

Yes, the core innovation in public blockchains, the double spend problem in trusless networks, is not present in private blockchains and private blockchains can he simplified with basic block that have existed for decades.

The biggest and critical issue with private blockchains is at the political level: how to make a lot of parties (e.g. bank) agree in a protocol involving critical things (e.g. money).