Does advertising do anything - if it doesn't why do companies spend so much money on it? This is basically a type of pro health advertising. We have anti smoki

Does advertising do anything - if it doesn't why do companies spend so much money on it? This is basically a type of pro health advertising. We have anti smoking advertising which has shown to be effective (https://www.abc.net.au/news/2015-03-19/australias-plain-packaging-laws-are-a-success,-studies-show/6331736 https://www.abc.net.au/news/2015-03-19/australias-plain-pack...). I think with a good advertisement strategy it can be very effective.