Perhaps because it is always drawn that way, that the same streamline gets separated then goes over the wing, then goes back together. Then in big letters it sa

Perhaps because it is always drawn that way, that the same streamline gets separated then goes over the wing, then goes back together. Then in big letters it says Bernoulli principle. Now that I read about it more, it looks like Bernoulli's principle is just conservation of energy - and as you say, there are no other requirements.