I made a FIDO token (a platform authenticator) implementation that uses the TPM to protect your private keys on Linux: https://github.com/psanford/tpm-fido
Anchoring to physical human interaction with a button or biometric sensor is a huge security property I don't think current gen TPMs can solve for.
In a typical implementation someone must be present at the machine expecting a tap, and tapping.
That said, overall this is a clever best effort for when a TPM is all a user has and you at least want to prove a given machine is involved in with.