I believe the danger is that it doesn't look difficult. Inexperienced climbers/first-time MR climbers might pass by the Final 400 because they don't see/recognize it or they think it looks too hard. So they keep walking till they think they've found an easier approach. But easy does not always equal safe, and difficult does not always equal dangerous. What looks like a short traverse to easier terrain could be deadly, whereas the Final 400 is just a series of easy ledges where you can always stand comfortably while pondering your next move.
