I was going to reply but exactly this - I'll add that the proof work in the article is really interesting and I love to see practical work in formal proofs happ

I was going to reply but exactly this - I'll add that the proof work in the article is really interesting and I love to see practical work in formal proofs happening as a result of eth in particular. However 100% proven code on eth I just don't believe is 100% trustworthy. Another way of phrasing it is that the law of leaky abstractions means that though the code itself might be 100% correct, lower levels can puncture the assumptions and make that correctness moot - IE, unsinkable titanic vibes