Not disagreeing with the statistics you posted.
But you are looking at social media in a vacuum.
End of the day Google will drive most of your haunts traffic, with the highest percentage of that traffic coming from organic rankings on google. SEO is extremely important for haunts.
So with that being said in 2013 and moving into 2014, google and SEO studies have shown that Social Media is becoming one of the biggest factors that affect SEO moving forward. Tweets of a certain url, faceook fans of a business linked to a url, google plus followers and G+'s on a url, twitter followers of a twitter account linked to a url, number of shares on facebook that a url receives, ect ect. Google and search engines are putting a huge focus on the websites that are doing a COMPLETE online marketing program, or doing everything right, not just writing good articles or changing some keywords. Now this means that your social media stategy should be much different than most people are doing, so if you are sitting there updating your facebook status over and over and wondering why your rankings are raising in google its because it isn't that easy.
Larry is correct, don't drop all your marketing and think sitting on facebook all day is an alternative. However their is much more too this whole online marketing formula than simply dropping one aspect because it doesn't show that it drives ticket sales directly. Everything works together and is a piece of a bigger puzzles, and SEO is just one of those other areas that active and powerful social media accounts help.