The amount of money devoted to branding and advertising by any company must, by definition, be seen as cost-effective, because otherwise it would cease to happen.
Ergo, branding and packaging must be a factor in consumer choice in certain products.
It does not always apply - sugar for example is always packaged in a bland format because sugar is sugar is sugar, so dressing it up would not encurage customers to select one brand over another.
But cigarette branding is clear and obvious, so it logically follows that removing that branding and neutralising the impact of visual appeal would go some way towards reducing the impulse to buy cigarettes.
It is by no means that only factor of course, but anything that helps reduce sales of a product that, if used for its intended lawful purpose can kill you, has to be a good thing.