[s3krit]

Engraved onto something like titanium would be better than a fireproof safe - they're only safe for X amount of time (I want to take a stab in the dark and say about 90 minutes?). This is how I have backed up some (since retired) crypto seed phrases in the past.

[tshaddox]

Where do you keep the titanium plate? I'd be more worried about losing it due to a natural disaster than merely having it destroyed beyond readability in a natural disaster.

[dylan604]

What happens if there's a typo in the engraving? Who's doing the engraving? How much do you trust the people you are providing the key to do it? When does the paranoia kick in vs being diligent?