Lower BB height is a practical consideration for making python easier to walk. Not sure how other riders feel, but struggling to keep the BB from falling down while walking the bike is perhaps the least "cool" aspect of the bike for me (clumsy). There had also been discussion about walk-ability implies ride-ability (not vice versa), which is a good test for builders who have not learned to ride yet. Higher seat height also makes it easier to learn/ride. Another practical consideration is for riders with weaker knees. It seems that optimal BB-seatHeight (15-20cm?) may cause encourage over exertion. Higher BB seems to intense for python cruising style, so it seems lower BB is the lazy way to go... Cheers, Vi