I thought Appcelerator Titanium was supposed to compile to native code? I downloaded it myself, saw all the HTML and JS files in the package and wondered, what the heck is the point in making this a standalone app instead of a web app. It's a ton of UI for a very simple to-do list. If it's just a webpage running in WebKit, and this is all the binary encapsulates, I see no reason to put it online, and then add http://fluidapp.com/ to allow people to use it offline as a desktop app, if they really want. Or, just use HTML5 manifests to make it work offline in any browser.
I think the general point is that for certain apps, a native environment is better suited to allow easy access and organization mentally. For a to-do list, it makes some sense. That way you can ⌘+TAB over to it, add or check your to-dos, then go back to whatever it is you were doing without worrying about browser tabs.
Another benefit is that you don't have to worry about cross-browser compatibility. If it looks good in your app on your dev computer, it should look the same on everyone else's.
I do agree that since it's written using web tech, they should have a web accessible version as well. Maybe they do, and I didn't see it?
Regardless, I think the end product is more important then HOW they made it or what language was used. If it works great and looks great, who really cares?