Like everyone has said, it's just fun to go and find new stuff. Sometimes the bits you can access just get boring. It's not like it's got secrets everywhere.

Some people I've seen also use it to portray themselves has someone from PC in GraalCity, who I knew for a fact wasn't. He said that he couldn't be an 'iPhone Noob' because he knew there was an Insane Asylum, on a hill to the far left of the Orphanage. So, I guess it's also for the knowledge, and looking cool, just like IRL.