An example would be the EOS 911 accounts. Users that can prove with an Ethereum transaction that they lost their EOS key can request a key change from ECAF or directly from block producers. Many users have requested this specific service and my guess is this will become the first use case.

I see this as another tool just like the referendum that will be needed for governance. It doesn't add new functionalities, but simplifies an existing one and makes it more transparent. Every action actually taken with this tool will still have to be approved by BPs.