Re: PGP crypto keys..
IIRC, a device with a fingerprint scanner is a lot safer as you cannot be forced to unlock the device.
1 - I'm not sure that is true. I know a PIN is protected, but FPs?
2 - you're there, and so is the device. It's easy to bring both together
3 - the FP readers on most devices suck badly, and that includes the one on iPhones. You have a shiny device which happily stores the required fingerprints for you, and it takes not that much effort to cook a fake finger from that so I don't think that's safe at all.
Ideally I'd like to have a device that still asks for a PIN or password after an FP, so that it either takes two passwords (as FP backup) or one FP plust maybe a shorter password to enter the device.