I think everybody knows this, but I don't: what is the use case of something like a private blockchain with smart contracts?
There's a number of applications for permissioned blockchains, perhaps even running in a "public" context. But the main application so far is inter-organizational transactional systems. Smart contracts in this context are as useful as in the public case (aka Ethereum), for defining and socializing business logic and processes. Fixed consensus membership doesn't fundamentally alter this.