It might not be because they are secure, but simply because the ROI is just a mere phone handset! Add to that the device, OS, and carrier variations. Read more here: http://mobile.slashdot.org/article.pl?sid=09/03/25/1238246&from=rss and here: http://www.computerworld.com/action/article.do?command=viewArticleBasic&taxonomyName=Mobile+and+Wireless&articleId=9130346&taxonomyId=15&pageNumber=1