Paid search advertising costs money, which at first may seem like a disadvantage, but these costs can easily be managed. With cost-per-click (CPC) or cost-per-thousand-impressions (CPM) campaigns, you spend as much or as little as you want. You can adjust your campaign budget at anytime, so if your business is going well, you can spend a little extra to drive traffic to your website and catch the attention of new customers.
Google claims their users click (organic) search results more often than ads, essentially rebutting the research cited above. A 2012 Google study found that 81% of ad impressions and 66% of ad clicks happen when there is no associated organic search result on the first page. Research has shown that searchers may have a bias against ads, unless the ads are relevant to the searcher's need or intent 
Remember when you used to rely solely on search engines for traffic? Remember when you worked on SEO and lived and died by your placement in Google? Were you #1? Assured success. Well, okay, maybe not assured. Success only came if the keywords were relevant to your site users, but it was the only real roadmap to generating site traffic and revenue.