To help explain how SEO is powerful than ads, we'll talk about how online ads actually work. Online advertising is what is called "push" advertising. Companies are pushing ads into your viewing experience in the hope that you will eventually click on the ad and purchase their products and/or services.
Google Adwords (or similar tools like Facebook® Ads) have certain demographics that you can pick to limit who sees your ads. You can choose from factors like age, race, sex, etc. But, there is a limitation to the extent of the effectiveness of ads. For example, even if you're playing Fortnite every day, YouTube will frequently show you an ad to install Fortnite because you fit the demographic Epic Games® entered. This means that Epic is spending money to advertise to someone that is already using their product. Now, this is just an absolute waste of time and resources.
But SEO is "pull" advertising. When someone does a search for your product or service, and they find you, that is pull advertising. You aren't putting an ad they may or (more likely) may not want, you are showing up when they are actually looking for you..With SEO, you're advertising only to the people that are interested in services similar to the ones you're providing. If someone searches best vacation spots, the person won't be looking to buy a PS4, he's actually looking for a good vacation spot to take some time off. There's no marketing tool out there that can really go for a targeted audience like SEO can. Neil Patel, a marketing guru, swears by doing SEO first.