[oblio]

You'll understand that "some reason" when you'll want some cool, fancy, useful app and the vendor will have not developed a version for your current mobile OS.

[TeMPOraL]

Few of web apps are useful, though, and all suffer severe performance and UX penalty by the very virtue of being run within a browser.

[oblio]

Few of any kind of apps are useful.

The non-purists (which is most people) have decided that availability trumps everything.

I was more of a purist, myself, but after some bad experiences with the lack of native apps, I'm more of a realist these days.