What I see missing in most of those is that decentralized immutable storage is the only part solved by blockchain technologies, and: - Storage is not the hard

What I see missing in most of those is that decentralized immutable storage is the only part solved by blockchain technologies, and: - Storage is not the hard part of all those proposals. Standard formats and a shared ontology between all players is the actual hard part. Medical records are useless if you can't read them. - Immutable storage is not hard to do in a centralized fashion and can be made much more efficient. Do blockchain-based systems offer the bandwidth to ingest _all_ medical records produced worldwide? I'd say the required amount of records-per-second would surprise you (as well as the potential size of those records, where some are high resolution scans and stuff like that). - Usually you _don't_ want immutable records, even when it seems like you do. What happens when you want to advance the formats stored in the blockchain? You can't edit old records (to update them to the new format), so your only options become: create a new blockchain and/or keep the cruft forever. - Storing anything private via encryption poses problems in many domains: sometimes you want certain third-parties to be able to access that information (e.g.: the hospital should have access to your medical records if you get there unconscious in an ambulance). I've seen no real solution to the kind of issues that arise there. These are very serious limitations against blockchains _shining_ if you ask me. Of all your proposed use-cases the only one that I can't see hitting those issues is the company registry records one (and maybe that's because I'm not acquainted enough with that domain).