Visiting what?

I read a wonder post over at Slacktivist today, and while reading the comments I came across something I read about a lot over there. Visiting pastors. People who's whole job is to visit people who need comfort in the parish (church? whatever, you know what I mean).
This is so strange to me. I remember when I was growing up my brother was in an accident and had to be hospitalized for months. My grandmother had the minister of our family church drive from New Jersey to sit with my mother in the hospital. Talk about a sucky job. But he did it. Not some other guy either, the minister I saw on the big holidays when we drove to Jersey (Easter and Christmas).
If some random dude had showed up Mom would have sent him back to Jersey. No offense to him. But that's just not how our church worked.
Some random dude showed up after Lil was born. I guess maybe he was a visiting pastor or something. A hospital pastor, maybe. But it's a strange concept. You have one guy who isn't the big guy who's supposed to come out and give you comfort. Most people have friends for that. With the added bonus that you actually know your friends.
Am I missing something here? Do you actually know the visiting pastor well before he shows up when you need someones shoulder to cry on? Are they better at giving comfort than the regular guy? Anyone have any ideas? Because I'm at a loss.