We have considered both of those attacks and address them in section 2.2 and 3.2 of the white paper respectively[1]. The short version is the key extraction attacks on this specific hardened chip are more expensive than the value they escrow, and in the event a key was extracted it creates a race condition at the period of claim not during the lifetime of its use - still providing some utility. What Kong does that Casascius didn't is provide guarantees that the minter never saw the private key.

[1] https://ipfs.io/ipfs/QmRNRCocj4PwKMXrd1jeUGw7ASQSuEk7BDJu5Ks...