What role does the marketing function play in creating value for customers and shareholders?

Marketing gets the products information to the consumer. The better the marketing, the more people want the product.

It benefits the shareholders who sell the product by attracting more consumers to buy it which puts more money into the company's hands.

The only benefit to consumers is that they will see the marketing (tv, radio, billboards, internet, etc....)

The downside to the customers is that they may have been talked into buying something that they didn't need.