Agreed all around. It is good to know what riding at many different angles is like. At 66 degrees, my board was strictly for carving only. (well, I would force it to do other things sometimes, but it was never all that fun.) At 58 degrees, the whole mountain is my oyster.
People can carve on whatever if they practice at it, so I can't tell you, Scott, what is "too low". You should see Seth Wescott carve his bx board in person. To draw an analogy to motorcycles, when I go to track days, there are guys there on friggen motocross bikes with street size wheels and slick tires and they embarrass a lot of dudes on sport bikes, myself included. But ultimately the fastest racers are on sport bikes for a reason, and the best carvers are on race boards with hardboots and angles around 55 to 65 degrees. Personally I would say 50 is too low.