I've ran out of reasons to use merit points. I have everything I need from these new fights. If they implemented this, then I would once again have a reason to merit.
You get CP from the exact same things as merits though. Therefore, since you want CP, you still have reason to go out and get it. By being able to convert merits just because you're allegedly done with the high tier battles (which of course we know there will be more) you're able to get far more CP than people who aren't "done" with them, which doesn't seem fair to me. You essentially get to double dip.