This is a good question, where gambling is promoted on billboards through banner ads, why is alcohol not promoted there. In fact, gambling gives a person a lot of pleasure and at the same time dreams of winning something big, although there is a high chance of losing, people enjoy it. However, in the case of alcohol, although it also gives a person pleasure, it is very harmful to a person. Consuming alcohol causes a lot of physical damage, which can even lead to death. Especially, an important organ of a person, the liver, is damaged. Considering everything, alcohol is not promoted through billboards. This may be a policy of the health department of a country.
The alcohol advertisements permeate everywhere, and the around the bottle messages such as drink responsibly are just placed as a formality and not actual warning. Still, alcohol has such impact, so many social and health issues are created by it, and it is legalized and popularized. Gambling, by contrast, is more limited in its advertisements since it may cause personal bankruptcy and addiction that may be more difficult to measure but no less disastrous. It could be just that, social attitudes, alcohol has been accepted throughout centuries whereas gambling is still in many cases considered as taking a gamble or even corrupt. Both should be more educated and controlled, and it is true that the lack of consistency when treating the two individuals is unfair.