Propaganda, which is what advertising is, is generally a way to trick people into doing things that they wouldn't otherwise have done, typically by making them believe things that are not true.

In the case of advertising, those untrue things are usually "X is a much bigger problem than I thought" and "Y will solve problem X and make my life a lot easier". That you can convince people of these things doesn't make them true in all cases. Washing machines are extremely useful; egg cookers, very much unnecessary. Yet commercials will often look the same for both kinds of products (not for washing machines today, obviously, as the case for why they are useful to have has long since become obvious, and commercials are mostly about which brand is better).

This is an often overlooked thing in discussions about advertising. A major part of the propaganda effort is not "which brand of X should I buy", it's "I need to own an X". That's where they lie to people the most, and convince them to waste money, not on an inferior product, but one that shouldn't have existed at all.