Actual benefit is that you invest your money in advertising, and get nothing back. Only very large companies can invest thousands of USD in Web ads and may be get something back.
SEO has a longer shelf life, too. The benefits of paid advertising only last as long as you continue
to pay for the advertising. SEO - organic SEO, at least - has more lasting benefits. As long as you
keep your web site current with fresh content, your site is well optimized, are promoting your
content on social media, etc... you will continue to reap the benefits.