Paid advertising can put a specific offer in front of people this week. SEO makes the pages you own easier to find for the services you intend to keep selling. They are not substitutes.
Use paid when you have a page that continues the promise and a person who will handle the replies. Use SEO when the site’s structure and wording match real searches. Using both without that page wastes both.
Decide the job of each channel for the quarter. Adding every channel is not a strategy.