We don't know the reason why because there wasn't one made public. it's literally impossible for us to know why this happened. Maybe it was an oversight, maybe they just didn't care the first time around and decided to change it later, maybe it was the sort of logic that sumwun mentioned but then for some reason we also don't know changed it back or maybe they had balancing issues. We just straight up don't know and have no way to find out past speculation. And the quality of speculation doesn't get any better than what I just said.