> It doesn't limit you to a single in-memory representation of each entry in a remote database.

If you have a remote database then you likely have multiple processes at play. For safety in those cases you need to rely on transactional safety at the database level or if transactions are not available then you may want to use a tool like TLA+ to check your distributed algorithm.

The example clearly has that though, otherwise it would not need

  yield from server.update_balances([payer, payee])

(The above comment was changed. When I replied it was talking about different threads reading from a database.)

In that case you’d be relying on the database rather than the programming language to manage shared state. (The article is more about how to safely manage shared state within a process.)

You could probably do it for a key value store, but I think it would take a custom database to do it for a relational database.