To see him doing this stuff before he can score political points shows that this is the real him. Not a put on. The fact that he's called on to do these events shows how much people respect him and think he can help. Here's a link to the blog post on the BarckObama.com site, asking for help, "Hurricane Gustav: How You Can Help".
Barack Obama, not only talking the talk, but WALKING THE WALK- UPDATE: McCain jokes about Katrina