This proves Authentication, not key storage that enables encryption/decryption. Per the paper, for authentication "a participant is presented with multiple SIS

This proves Authentication, not key storage that enables encryption/decryption. Per the paper, for authentication "a participant is presented with multiple SISL tasks where one of the tasks contains elements from the trained sequence." Hence the system must already know the secret password. If that system is your laptop, then the feds already have the key when they seize it and don't need to resort to rubber hose or its russian variant thermal-rectal cryptography. Also, the paper assumes physical presence of a live human at some terminal for authentication. At the point that you can make assumptions about who is operating your authentication system, biometrics seem to be a far faster and more reliable authentication system. Both those limitations,however, could change with further research.