Here's one overlooked reason why apps are better than websites: no passwords! I absolutely hate that every time I had to use the mobile GMail app I had to enter in a password again, even though everything else has a native app feel.
Imagine if someone found your phone with email logged in. They would immediately be able to scan through your email for registration confirmation emails, go to that site and reset the password giving them complete access. If one of those accounts was for a site which saved cc details and had something the thief wanted (or could sell), they can drain your card with out setting off any fraud warnings, because you wanted to convenience of not having to type your password every time.
I agree that it's troublesome that people have their phones set up so that anyone with physical access to an unlocked phone has access to everything. But I'm inclined to think of that as a symptom of the problem rather than the problem itself. The root of the problem being that too many folks who draw up security schemes don't seem to grasp the most basic lesson about how people deal with security: When given a choice between excessively inconvenient security and no security, your average user will always opt for no security. If that's not an option by default, they will figure out a way to make it an option, and then opt for it. (Sticky notes, y'all.) If there's no way to make it an option, they will go find someone who lets it be an option, then opt for it.
One great thing about non-biometric authentication systems is that it's easy to replace a compromised keycard or password. Replacing your own fingers, not so much.
Aren't we talking about alternatives to conventional password entry because it is a great nuisance?
Voice recognition, Face recognition and Finger Printing all seem reasonable alternatives. I do believe it is a matter of time before they become viable in smartphones.
How about an RFID chip in your wrist watch which makes your smartphone log in. Outside of a meter or two, it will ask for a complex password. Why not? I will buy it :-)