I think you misunderstand how private blockchains work: > "they can do the job more efficiently" They ARE doing the job more efficiently by not using proof of

I think you misunderstand how private blockchains work: > "they can do the job more efficiently" They ARE doing the job more efficiently by not using proof of work, and instead most likely going with a quorum approach based on public keys. > it does not give incentives to the banks to spend a lot of computational power to the network Right, because it doesn't use proof of work, it uses a quorum vote. The banks would still need to form a cartel in order to get a (super)majority of the vote.