So sounds like Australian smart meter companies are better at security than British ones.
The energy usage tracking can be done without smart meters, in this country electricity companies (and lots of private companies) offered induction clamp based electrical usage logging devices. These may not have been quite as accurate as onboard measuring but this could have easily been solved with some kind of serial protocol exposed on the meter which a third party datalogger could attach to. The ability to track energy usage is not a feature of a smart meter, it's just a feature of having access to the meter's data, this data could always have been made available even if the meter wasn't networked.
Open banking is a complete disaster that I seriously don't think deserves the name "open". I still don't understand how an API which requires you to be a BANK to be able to interact with can remotely claim to be open but having tested some of the implementation for banks it's some horrific over-engineered mess.
Let's hope the data access API for your meter doesn't require you to be an electricity company to access it. As it stands, in the UK, meters are not intercompatible between utility companies so if you switch providers (which I do annually) the old smart meter just becomes a dumb meter again.