well, that's the centralised implementation, which i also don't like. iirc there's a decentralised implementation where, instead of tracking your location and sending it to a central server, each device would have a uuid. whenever you come near someone, both of your devices would just swap uuids and take note of them, and if either of you catches covid, they can just open that list of collected uuids and use that to notify the people who came into contact with them. imo not only is this more privacy-friendly, but it saves infrastructure costs from not having to host centralised servers.

What government/country was this, out of curiosity? I thought the whole point of the local-storage-only approach was protecting privacy, so curious how it could be used in investigations.

Got a source for that? The approach google and Apple implemented was completely anonymous, even with rolling identifiers.