Why is this hard to understand? The CPU and platform is marketed as having an fTPM, but everyone's experience over the last 3 years is that it's faulty. It doesn't matter if there's an alternative solution involving buying a separate device, and it doesn't matter if you think the fTPM isn't necessary. The point is that the features they claimed to support were faulty, untested, and unfixed for many years. That's not acceptable.
Also, your description of how an fTPM works is wrong. The fTPM on AMD is provided by the AMD PSP TEE, which measures your execution environment then seals the drive encryption key. The platform garauntees that it will not unseal the drive encryption key other than to the same combination of trusted hardware and cryptographically verified software that previously sealed the key. The hardware is tamper resistent and has a relatively good track record. dTPM vs fTPM is an active debate, but so far the most practical sniff attack on the TPM only works on dTPMs, though that's partially Microsoft's fault.
If a hard drive is stolen, it is useless without the CPU. If a whole computer is stolen, the data will only be accessible to a very advanced adversary. The list of people on earth who can tamper or trace a CPU to successfully exfiltrate an fTPM key is probably a short list, and nearly all of them will be security researchers, state-level adversaries or APTs. In fact, many government and other highly secure organisations rely on the security of the TPM for disk encryption.
Analogy wise, it's more like having a bouncer guarding your door who only lets you in once he's carefully checked all your biometrics. And if you try to push past him, he blows up the house so you can't get in.
However, would I trust a TPM in isolation if I was likely to be physically raided by the CIA? Probably not.
Also, your description of how an fTPM works is wrong. The fTPM on AMD is provided by the AMD PSP TEE, which measures your execution environment then seals the drive encryption key. The platform garauntees that it will not unseal the drive encryption key other than to the same combination of trusted hardware and cryptographically verified software that previously sealed the key. The hardware is tamper resistent and has a relatively good track record. dTPM vs fTPM is an active debate, but so far the most practical sniff attack on the TPM only works on dTPMs, though that's partially Microsoft's fault.
If a hard drive is stolen, it is useless without the CPU. If a whole computer is stolen, the data will only be accessible to a very advanced adversary. The list of people on earth who can tamper or trace a CPU to successfully exfiltrate an fTPM key is probably a short list, and nearly all of them will be security researchers, state-level adversaries or APTs. In fact, many government and other highly secure organisations rely on the security of the TPM for disk encryption.
Analogy wise, it's more like having a bouncer guarding your door who only lets you in once he's carefully checked all your biometrics. And if you try to push past him, he blows up the house so you can't get in.
However, would I trust a TPM in isolation if I was likely to be physically raided by the CIA? Probably not.