You have to consider that it's trivially easy to extract the full fonts from the app the enduser receives. For iOS just unzip the .ipa file, go to the Resources folder et voilà.
I thought that too might prevent foundries to license their fonts, but it turns out that services like typekit are in fact already putting these fonts online, without any real guarantee against pirating. It's just not very convenient to do right now, but definitely doable, as stated by typekit themselves : http://blog.typekit.com/2009/07/21/serving-and-protecting-fo...
So, if foundries are allowing that on the web, why the special treatment in native apps? That is one of the points of the article.
If someone is able and willing to do that, wouldn't that person likewise be able to extract the full fonts from a website using such a font? If so, I'm not sure what your point is.
