From a marketing perspective - I know lots of people and blogs who monitor the app store for new apps and try them out. An HTML5 app means that you will not have access to this crowd.
One thing I constantly see in the mobile deployment conversation is a focus on only end-user. There is a huge corporate enterprise market there as well. Since this is where I make my money, my decision tree is a bit different. Corporate clients generally target a more limited number of devices. Also, the app store would not be a likely repository for MIS to deploy from. There is a much bigger market than the end-user only apps that most of these points reference. HTML5 and webkit make good sense on the enterprise Intranet.
