Passphrase are not stored on hardware wallets that I know as of now, if the robber was able to see the seed phrase, he can not be able to have access to the passphrase, if the robber do not have access to the passphrase, he is not going to be able to steal the coins.
The robber goes home, and creates a new wallet with his own new hardware wallet ( it gives him the option to recover using the 24 words
I think in reality, the robber may not have hardware wallet, and he can not be that patient to first buy hardware wallet, he will follow the unsafe way which is the use of online wallet, but the passphrase will protect the coins as long as the thief do not have access to the passphrase.
The victim can just move his coins to another hardware wallet or a safe and properly generated cold wallet.
OK thank you for the reply.
Let's just say... the robber is a pro-Bitcoin thief, he has a few hardware wallets back at his pad.
I guess it doesn't matter, I mean he could create a new wallet with Electrum or Sparrow.
I was just having trouble wrapping my mind around this concept....
... so he would recover the non-passphrase wallet, but by doing so, it does not mean the passphrase wallet is now inaccessible to the victim ( who still knows the passphrase + 24 words )