- the embedded view doesn't behave the same as the browser (for example, features like pinch to zoom and your login status on websites)
- It's difficult to share a page in that view with other apps (like Facebook, Twitter, your Bookmarking app, Evernote)
- Chrome or Firefox Sync doesn't work with web views
- the page isn't in your browser history, so finding it again is hard
- some web views capture all links (I'm looking at you Feedly) so clicking links in the loaded page loads different pages still in the view. Now how does the back button behaviour work?
- some links point to pages that I have an app for (that advertises support for those URLs, YouTube is one, Glimmr [for Flickr] is another), I want those apps to show those pages as they do it better than even a web browser, so definitely better than a webview
- the Android design patterns expect apps to inter-relate via the Share mechanism. Embedded webviews are stolen from iOS which doesn't have that capability. Don't ape another platform!
(Sorry for doing a list, "x things" type blog posts are annoying aren't they?)