[ahnick]

Some devices derive their keys from a recovery seed that you can store offline in paper form. The benefit of this approach is that you can recreate the key on a backup device using the recovery seed, should you lose your primary.

[kelnos]

Ah, neat, so basically the recovery seed would let you buy a new device and then use it to "clone" your old one?

Definitely useful in case you lose it or it gets stolen, but you'd end up wanting to rotate to a new key with fresh seeds anyway, since the old key could be in the hands of an attacker. I guess this is still useful in the case where you don't lose the old key, but instead damage or destroy it by accident.

[ahnick]

Yes, exactly. If you lose it or it's stolen, then you'd want to rotate to a new key quickly. Some of these devices have a pin too, so the attacker needs to crack the pin before they can actually use the device. This should hopefully buy you enough time to bring up a new device and switch over accounts. That's why it's probably a good idea to buy your second device when you buy your first one and store it in a separate, reasonably secure, but more importantly, quickly accessible, location.