It slightly affects the 'feel' of the up-swipe motion when using the phone. When the bottom part of the case is open, there is a smoother feel to the up-swipe. When there is a raised lip at the bottom, following the other three sides, it feels less smooth and very occasionally misses, when you haven't swiped from the very bottom.Looks great. Why are people objecting to the closed bottom? I think it will protect the phone more.
A VERY minor quibble, but I think that's the reason for liking the open bottom.