Whether you work in design,
Advertising helps people and nudges them to basically buy more.
It educates the consumer about the product, why it is better, it’s uses etc.
By encouraging increased spending, it helps the economy to grow.
In a recessional economy you might find a downward momentum in advertising in order to cut costs buy marketeers. But at the same time it is also possible to find another marketeer increase advertising spend in order to grab the market and surpass the competition.