The real world doesn't work that way. Business collaborate one day and compete the next (or even the very same day). Even when collaborating they don't want to share all information, and certainly not with every member of a group. To control access to information once access to the blockchain has been granted at all, privacy features are needed.
...
There are multiple choices for what level of privacy and sharability a permissioned blockchain may have in an actual company. Not in technology terms, but in business process rationale. Certain blockchains may not be accessible by a competing/cooperating company at all, just like you are not giving away the direct access to your database/CRM.
The time will show the corporate blockchain use cases, but I do see your point though. I believe I have to refine what I've been saying. Permissioned blockchains will need the privacy features to define the level of data access for the participants. However, this doesn't have much to do with the zero-trust privacy. This may have more to do with centralized privacy and centrally assigned roles.
Honestly, I haven't given much thought to the potential architecture of such a solution. It may well not be existing, or it might have a semi-centralized form (masternodes, anyone?). However, intuitively I'd say that ringsig is a clumsy option in this case.
There's a brighter side to my original post if you wish: focus on the bigger commercializable issues.
...
Hide Data, Not IP
...
So the government can still identify who is making those transactions and compel you to reveal your private keys or face the gulag, but in the normal use of the public block chain privacy is retained (to the extent it doesn't leak into non-hidden layers but that is the current world situation any way, so no worse).
...
Mix Data, Not Identity
I believe I'd agree with you on the theory. However, I'm still not sure how it may take off in the real world. IMO the discourse is utopian. I'll need some time to think it over.
So, are you out of Bytecoin now (i.e. own none), Rias? Just curious.
Cheers, Q
I own some BCN. Partly, because I still believe it to have potential (waiting for the roadmap to be executed).