I doubt the reason is of the shot angle or the precision. Furthermore, I consider this shot as "less safe" against fails, because of the unstable foot positioning. (fail example) Initially I was thinking the shooting foot remains the same, but i was wrong - but still I'm wondering if that's really the argument for that kind of shooting?
EDIT I don't know if that technique has a particular "name", e.g. like the "elastico" trick, therefore I don't know a better title for my question.