Well, a good reason to do it is to see whether the change causes GE failures, bugs or super-strange results (like 50 Blocks a game or such), so it´s not completely useless from a Beta-Testing point of view.
Then again, PL users would probably benefit from that testing opportunity, and one of the major principles in Buzzerbeater is that "paying" won´t make you any more likely to win. So there is some credibility in the approach not to run it in the PL for now.