Hardware wallets and steel mnemonic back ups serve different purposes. No hardware wallet is going to be a physically resistant as a good steel product, but a steel product does not let you sign transactions without importing your seed phrase to a computer (and all the inherent risks that come with doing that). They are complementary devices, not mutually exclusive ones. A hardware wallet is used for interacting with you private keys in a secure environment, keeping them offline, but still allowing you to generate new addresses and create and sign transactions. A steel back up is used for long term back up of your seed phrase. It is entirely sensible to use both.

Note that both the Ellipal Mnemonic Metal and the Cobo Tablet performed very poorly on stress testing, with both resulting in complete loss of data - https://jlopp.github.io/metal-bitcoin-storage-reviews/

Also note that the Ellipal hardware wallet had a vulnerability which allowedthe seed phrase to be extracted - https://donjon.ledger.com/Ellipal-Security/.