So Google, Amazon, Apple, and many other large companies in the IoT space are using a blockchain as a federated data store: github.com/…/distributed-compliance-ledger

It stores the data needed for Matter [ en.m.wikipedia.org/wiki/Matter_(standard) ] device attestation.

I think its an interesting use case on how entities that don’t particularly trust each other can operate a federated system. Accounts are linked to an identity out-of-band in order to have write permissions to the chain. When an account writes, all the readers of the chain have reasonable assurances of the author of that write. No company can inject false state as another company without that company’s guarded private key. All transactions are also auditable as an additional assurance the data isn’t undergoing a malicious act.

tl;dr; interesting use cases for tamper proof federated ledgers.