Of course it is not the only criteria that should be considered.
Governments have a duty of care towards their citizens. Thats why there is legislation regarding the use of , for example, car seat belts. Thats why they are reviewing the area of cosmetic surgery. Thats why society offers care for the elderly. Thats why we have a national health service!
Whatever you think about smoking, the facts are very simple, and very straightforward. Smoking is extremely bad for your long term health.
Cigarettes are extremely addictive, making quitting difficult and smoking bad for your pocket. Off the top of my head, they are the only legal product, available over the counter, that, if used as recommended by the manufacturer and as designed, will kill its users - in the thousands annually.
Its not as if the Aussies were baning smoking altogether. Regular smokers will still be able to purchase their daily fix of nicotine - but they new packaging will graphically illustrate the risks they run. And such packaging may very well discourage new smokers - A measure surely to be welcomed.