Lots and lots of people search for things. That traffic can be extremely powerful for a business not only because there is a lot of traffic, but because there is a lot of very specific, high-intent traffic.
If you sell blue widgets, would you rather buy a billboard so anyone with a car in your area sees your ad (whether they will ever have any interest in blue widgets or not), or show up every time anyone in the world types “buy blue widgets” into a search engine? Probably the latter, because those people have commercial intent, meaning they are standing up and saying that they want to buy something you offer.
People are searching for any manner of things directly related to your business. Beyond that, your prospects are also searching for all kinds of things that are only loosely related to your business. These represent even more opportunities to connect with those folks and help answer their questions, solve their problems, and become a trusted resource for them.
Are you more likely to get your widgets from a trusted resource who offered great information each of the last four times you turned to Google for help with a problem, or someone you’ve never heard of?