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.