The high straddle cable is likely because the arms are so long. Low straddle cables was the trick BITD when trying to get maximum leverage out of shorter armed brakes. The trade off, of course, is that high leverage means less travel, squishy feel, and potential close tolerances and rubbing if your rim is slightly out of true. A higher cable means the arms will move in more for each mm of cable pulled from the levers. It also means that the dreaded 'negative force curve' (the harder you pull the levers, the higher the straddle cable goes, and the less leverage you have pushing the pads against the rim) will be less than with a low straddle cable.
I would guess that if you wanted to use a low straddle cable, you could do so with V-brake 'long pull' levers and get acceptable brake performance, but that's just a guess.