It seems like the benefits are having the device lock/wipe itself after a set amount of attempts in case of a brute force attack and not having to run software to decrypt the drive on the device you plug it into.
I included a picture of the IronKey Keypad 200 but that's just because it's the first result that came up when I was looking for an example. There seem to be a few other manufacturers and models out there and they probably have different features.
I am curious what do you think of them? Do you think they are useful? Do you find it more a novelty?
It was an ExplainingComputers video titled Very Useful Small Computing Things that made me think of them.
That's why I said to combine it with something else. Jenny's number might be in a dictionary that is used in a brute force attack but hopefully something like your middle school locker combination isn't. It's still 7 extra bits of entropy.
Password Entropy = length * log~2~(possible_chars). So this would actually add 7*log~2~(10) => 23 bits of entropy, assuming the attacker knew that this section was numeric, or ~45 bits if they didn't.
For anyone curious: Current best practice is a minimum of 100 bits, or 16 characters assuming only letters, numbers, and special characters. The recommended minimum bits increases every year with computing power.
Thanks for the correction
(yeah yeah but that's not funny so I ignored it :p)