This solution is born out of frustrating of constantly being spammed by recruiters. If you have this as the only email address they can contact you at and you enforce it they will have no choice but to bend to that.
That concept only works if the majority if tech professionals use the service.
Well to reveal more of the strategy behind that, my team and I are tackling the DMV area first. The recruiters are pretty aggressive with contacting professionals in this area. The developers have developed a blindness to these type of emails. The theory is if we create a pay wall only serious inquiries will pass through and create better response rates to recruiters from tech professionals.