There is no doubt that bicycle helmets save lives and heads from injuries. Like wearing seatbelts in motor cars, it is a no brainer.....oh, not an intentional pun, especially as I have a brother with an ABI, Acquired Brain Injury, and yes it was it bicycle he was riding when he rode straight across our Highway 1 without looking, possibly a suicide attempt. He can't recall. No, he was not wearing a helmet and the lack of could have caused more brain injury than he had been wearing one.
However, Melbourne's bicycle scheme is going to fail or at best being a large impost on City of Melbourne ratepayers, because the law says that cyclists must wear protective helmets. I would argue for an exemption for bicycle scheme hired bikes. The riders would generally be experienced and know the dangers, or be very occasional riders and be very cautious. The distances would be short. The is traffic generally slow and non aggressive, well better than some places. There are many paths for exclusive cycling where there is little interaction between cars and bicycles.
As per usual, I write this with some self interest. A rack with bicycles has appeared nearby to us, adjacent to the park on Kingsway we call the Little Sandy Desert.