Or The Bow's big head for that matter. or the former CBE's Family of Man statues. Two of our best installations with a high degree of interactivity both locked forever in a boring corporate plaza. They would make perfect additions to an urban plaza or river pathway where people could interact with them more regularly.
The route of all the issues with public art is that the art funding is connected to the location. Build lots of highway overpasses, get lots of highway overpass art. Build a big shiny office building and get a big shiny head at it's base. As others pointed out, this is dumb - it's completely divorced from where art can best be enjoyed. Melbourne's functional highway art is a cool idea, but more fundamentally - no one has ever visited Melbourne or enjoyed living there (or any city) because the highways look pretty.
I kind of get how we got here through politics. Having a public art budget disconnected from infrastructure as a standalone budget so it had the flexibility to be placed where art makes more sense would be just as much of a political lightning rod in some circles in this city as the current process. Further it could be even easier to defunded. That's not an endorsement of the current process, but understandable how it evolved as a negotiated outcome to connect the projects that get all the funding (highways) with the ones that get much less (art, sidewalks, pathways).
The key, as usual, is the public realm and pedestrian spaces. That's where art should be and where it would be best enjoyed. The Big Blue Circle is actually great and a nice bicycle ride to go check out in an otherwise fairly destination-less Nose Creek pathway - but I would have taken either a Nose Creek pathway extension further towards the edge of the city and no art or the circle located in a more prominent public park if I was offered a trade.