[Aaargh20318]

Consider this: you are working on your laptop in a public place, like on the train. or in a coffee shop. You log in to your company website. Anyone looking over your shoulder can see you type your password, as well as the webpage you're logging in to.

And it's not just people standing behind you, it can also be the security camera in that coffee shop. It can be someone looking through your office window with a telescope from the next building over.

Same goes for your phone. There are ample opportunities to see someone type in their PIN code to unlock their phone, especially if you use it for payments which are generally done in public places. No need for violence, no need to draw attention to yourself, just watch them enter their PIN and then pickpocket the phone afterwards.

It all depends on the exact threat scenario, but biometric authentication can be preferable to passwords when used in public places.

[FabHK]

When Ed Snowden accesses his laptop in the documentary Citizenfour, he puts a blanket over his head and himself including the laptop, then types in the password (presumably... we will never know :), and only then emerges from the blanket. I thought that was an excellent simple security measure!

Maybe a bit weird if you start doing that in trains and coffee shops though.