HSMs are very good because the key isn't stored in a way that allows an attacker to get it. HSMs have authentication systems, so you can ensure that only the us

HSMs are very good because the key isn't stored in a way that allows an attacker to get it. HSMs have authentication systems, so you can ensure that only the user can use the decryption key (but they can never get the actual key). Of course, you can misuse them to create proprietary jails for users, but they can be very good for device security.