The short answer...

An auto surf provides a steady stream of hits/traffic/visitors to your site.  While the members may not really be looking at your site, you can bet that the search engines are recording those page views.  When a search engine sees lots of activity, they send their "bots" out to look at your page.  More traffic/visitors/hits=Higher Search engine rank for your page.  The higher search engines rank your page, the more likely it is that people in search of the solution your website provides will find you.

There is no right or wrong answer when it comes to marketing your site. There is simply the answer (method) you choose.

If what you really desire is to have human eyes on your website, then a manual traffic site will be more to your liking, although they are more laborious & also have members that are clicking to earn credits to show their sites...not really looking for a new site to join. 

For that reason, I choose to look for advertising solutions that improve my sites search rank. People that search ARE looking for a solution to their problem. Your site is likely to be their answer.

 TopTierTraffic  Is a Manual Exchange and there are many really great Manual Exchanges Listed in our  Downline  Builder
 Building Blocks

OK, so the answer really is not that short! 

There really are two very different schools of thought when it comes to traffic exchanges & two very different reasons for using both a Manual and an Auto Exchange. 

Read More on how to use traffic exchange to your advantage- click here