[yakkityyak]

Zero is a stretch. I think they have largely failed to serve their purpose in the consumer device realm, beyond decent integration with BitLocker.

Despite the shortcomings, I think they are very useful devices from the perspective of running data centers. I consider it useless against evil maid attacks though.

[lostmsu]

I feel like BitLocker is a great feature. So great it's one of the few things keeping me on Windows. Would not call it "largely failed".

[Nextgrid]

I think they failed to serve their purpose because until relatively recently they've only been present on premium-grade machines, so software couldn't rely on the presence of one.

Nowadays with Microsoft making it a requirement (as well as fTPM which means the TPM no longer requires dedicated hardware) we might see more use-cases.