As I understand it you get paid $1.95 per 100K for adding liquidity if the order is subsequently filled (so you don't pay 2.95 and get 1.95 back, you actually get the 1.95). Anyone using them ? This might even make it worthwhile to write a FIX application to act as a market maker in some of the wider spread pairs.
You are asking more general a question: "Why exchanges pay for adding liquidity?" Perhaps, it's business sense. Markets with larger size on bid and offer attract more clients, which means more commissions.