TPMs are not 'trivially' bypassable. There's attacks on how they're used, naturally, but those wouldn't apply in this case. In this case the main issue is tha

TPMs are not 'trivially' bypassable. There's attacks on how they're used, naturally, but those wouldn't apply in this case. In this case the main issue is that once you've unlocked your storage keys you get to use them, and since storage keys need to be software keys to perform acceptably, you could even steal them. But if your device is off, a TPM would be more than adequate to protect local storage.