Obviously, access is power, especially in Washington, D.C. It's no surprise that the Obama administration would make this offer, and it's no surprise that those invited would take him up on it. "Relationships" forged at such events help journalists get other stories, and help politicians to get themselves portrayed in the most favorable light.
What's a little creepy is the almost-total blackout until now of the fact that the event even took place, and the dearth of knowledge about who was there. After all, an event can maintain its off-the-record status even if a reporter acknowledges the existence of such an event (and his/her presence there).
In the end, it strikes me that the chief problem is that most reporters don't just want to report on the Obama administration: They want to be the President's pal. They think he's the hippest, coolest, smartest thing since sliced bread.
The only downside for you and me? That means that the reporters are ignoring their most sacred obligations: To report without fear or favor, and to consider informing the public -- not pleasing the President, and not aggrandizing themselves -- as their top priority.