Because there's virtually no pure cbmm in the game atm. So whatever else is going on another sbmm playlist would just be overkill at this point. It would also be cool to have a cbmm playlist that iterates in the direction of CBMM based on the positive aspects of that matchmaking type and not so much iterating in the direction of sbmm from a cbmm starting point. Its not like the pure cbmm was perfect before. It also had its issues.