I would be interested to know if any other forum members have explored the tension between public ‘open’ blockchains and permissioned ‘closed’ blockchains … and how they see it playing out. Could intranet vs internet be a fair comparison? (Closed peer interactions vs network effects)
It seems to me the use cases for private blockchains are very limited. The point of a blockchain is to enable cooperation between people who do not trust each other. If you have to exclude certain participants and not allow them to write to the blockchain it means you do have to trust the participants in some way. Otherwise you it could just be public.
So perhaps it can make sense for a group of participants who for example trust each other not to spam but do not trust each other to make honest transactions.
Unless there is an authority with the job of granting write access to participants. In that case this authority could simply run a database instead of massively overcomplicating things by having a blockchain.