You could argue that it just happens to also be to your benefit by chance, but that's certainly not where the incentives lie.
By comparison, companies like consumer reports, which instead directly sell you information to influence your behavior to your benefit are tiny. The advertising industry is nearly a trillion dollar industry -- if a large amount of that value is going to the consumer why hasn't there been massive innovation in selling to it directly to the consumer?
GP's comment about selling us shit we don't want/need is a hard pill to swallow. It's highly counterintuitive and demeaning to our sense of agency -- just like so many results in modern psychology.
But I think that view also misses the bigger picture twice. First, because while the consumer-producer relationship is positive sum and that's the whole reason it exists, pricing is not. If advertising makes it easier to connect with a product you want, then the price can be raised. We should think about how advertising makes the things we want more expensive.
But second, I think we should also think about how the relationship of advertiser to producer may not be positive sum. Producers compete with each other in a fashion that isn't positive sum, and advertisers sell to all producers. That's an arms race. I can't effectively start a business without using advertising because all my competitors use advertising. Advertising doesn't account for a trillion dollars in demand per year -- it just siphons it from producers by selling them the same arms they sell to their competitors.