These ads are essentially telling customers, “FYI, product X exists. Here’s how it works. It’s available if you need it.”
Liquid Draino, for example, is a product that thrives on simple awareness, because drains don’t clog all that frequently, and if you don’t know what Liquid Draino is and what it does, you won’t think to use it
This is very product-dependent.
This can be extended to an ad existing in an expensive place, such as in times square or the super bowl. This is Cultural Imprinting