For one, it self-selects developers who are proactive, with a can-do attitude. They are most likely above average, so that in turn should attract good companies

For one, it self-selects developers who are proactive, with a can-do attitude. They are most likely above average, so that in turn should attract good companies. I know I would look around to see what talent is there. I know there is an argument that the greatest coders would not bother. That's probably true, but you may get access to the level immediately below: not bad...