It's true that the usual explanation with the Bernoulli effect is wrong, but the idea that the Coanda effect is important for normal flight is also wrong. The relationship between wing camber, angle of attack, and lift is a little more complicated than the post, or the presentation it references, implies. See http://av8n.com/how/htm/airfoils.html#sec-other-fallacies for more details.
A few planes have been built with the Coanda effect in mind (http://en.wikipedia.org/wiki/Boeing_YC-14), but in general it isn't very important.